The crux of your argument, that micro-gram level AL exposure has negative impacts, is based on the premature infant aluminum toxicity paper. It's a p-hacked piece of junk. They found no significant effect (P=0.39!!!) and then started analyzing subgroups until they got a p<0.05. Without adjusting for multiplicity, of course. Its implications would also only generalize to premature children. In addition, this study focuses on premature infants, not vaccine-age children. And blood AL levels were never taken! It's a bad paper and should be ignored.

On the other hand, this publication cites a paper noting that radio-labeled aluminum has 99.5% of injected aluminum being removed from the blood after 24 hours... but also that 50% is removed after an hour, and that it has a biological half-life of 7 years (!!??). Apparently, it mostly settles to the bones. This matches the 40-50mg total AL load figure I've seen elsewhere.

This brings us to Priest's paper, which actually explores the blood-brain barrier in regard to aluminum and it estimates... 8 micrograms of transfer from the blood to the brain per year. The brain has much lower levels of AL than the rest of the body. This implies that sudden spikes in blood aluminum levels simply won't have a major impact. Remember, aluminum can only cause brain damage if it reaches toxic levels. High blood AL only increases the speed at which brain AL levels increase. What really matters is the actual levels of brain AL, which is determined by long-term blood AL levels.

So let's look at chronic exposure. The average human consumes ~10mg of aluminum in their diet daily. Assuming 0.1% bioavailability, this is 0.01mg per day. Over a year, that's equivalent to a 4mg injection of aluminum. So more than you get from the entire vaccine schedule. 

Edit: I forgot children were tiny. Whoops. So you still get more AL in your blood from the vaccines than normal food.

Edit2: It turns out that people actually just went and injected premature infants with massive amounts of IV aluminum until some had toxic levels of AL. Apparently, some were getting 100ug of IV AL per day, most of it from non-food IVs (16.6 mg/L for potassium, which is just nuts). 

The infants in this study were injected with <3mg of IV AL over the course of a few weeks, and you see 10x levels of AL in all their tissues compared to controls. If we take ~100 ug/day, multiply that by 20 days, we get~2mg of aluminum. The highest blood AL levels detected was 172, so I guess in a worst-case scenario, for the Hep B vaccine at birth (200 ug AL), you can expect an increase of ~17 ug/L of blood AL for a few days/weeks? That seems fine? And every shot afterward is for a much bigger child, so I don't think it's too problematic. Premies also seem to have similar renal AL expulsion rates as adults most of the time. Except when they don't. I think you can maybe make a precautionary case about the at-birth Hep B vaccine specifically for renal-impaired premies, but not anything else.

And yes, it looks like the AL is sinking into the bones. A newborn has 80 g of bone on average, and 20mg/kg * 0.08kg = 1.6mg of aluminum. That's where it all went! The numbers end up working out, which is nice. 

Is there maybe a way for immune cells to carry aluminum directly to the brain? Possible. If you find a paper finding evidence of that, I'll take a look at it, but my intuition is that it's unlikely.

I'm amazed both by the substantial lack of key evidence regarding the effectivity and safety of at least some vaccines, and by the radicalization of the discourse everywhere, even here, where you can rarely express an opinion without being heavily censored or criticised. 

An example:

https://www.lesswrong.com/posts/Ccv8PinXRgRTKpGaj/what-we-ve-learned-so-far-from-our-technological-temptations?commentId=P9SMrtmmznTxF8q3Q

I gain nothing by doubting the effectivity and safety of any treatment. I don't work in the industry, I don't monetize my opinions, I don't even get social points. If I express my doubts is because I'm worried and want to know the truth. For some reason, this is politically incorrect in most circumstances. 

Why and how this topic became taboo? Even if I'm stupid, and ignorant, I act in good faith, I truly want to know and, in case I'm right, to help people. Why am I censored for asking questions and showing some weak points in the narrative?

This reminds me of when I found an error in a popular asteroid impact effects calculator. The calculator suggested that an impact would generate only very minor earthquakes. For instance, if the Moon were to collide with the Earth, it would barely be noticeable on the other side of the planet.

I reached out to the creator of this model. They responded by explaining that their data is derived from a study on the effects of minor impacts on the Moon, as measured by a certain Apollo scientific instrument.

The study concluded that minor impactors contribute less than 0.0001% of their energy to seismic waves. However, I believe there is a significant difference between minor impactors on the Moon and larger impactors on Earth. Minor impactors hit a solid surface, and most of their kinetic energy is directed into ricocheting debris, with only a tiny fraction becoming sound waves.

In contrast, larger (kilometer-sized) impactors on Earth would penetrate deep underground, and the Earth's surface around them would behave more like a liquid. This liquid-like surface would create a large 'splash', and a significant portion of the impact energy would be converted into waves—I estimate this to be between 1 and 10 percent.

Consequently, I believe that the seismic effects of potential impactors are underestimated when compared to more widely-recognized effects such as global tsunamis and climate change.

If you want to read more about the science behind aluminium adjuvants, http://vaccinepapers.org/ is a goldmine of info mainly about aluminium in vaccines. 

http://vaccinepapers.org/the-foundation-for-al-adjuvant-safety-is-false/ is also worth a read. 

TLDR: the science behind the safety of aluminium adjuvants is sorely lacking.

-Alternatives to aluminum exist, including mRNA and other new adjuvants.

This is not really true. Despite aluminium being a neurotoxin that is detrimental at any dose just like mercury, with identical neurotoxic effects as mercury, no viable alternatives exist that were as extensively tested, and most alternatives are in fact much more dangerous. I'm not an expert on mRNA, but we have all seen with the covid shots that the side-effects were much more extreme. And for all we know it didn't need adjuvants because the spike protein itself is cytotoxic.

This is not to say that we can't develop better adjuvants, for example by using natural chemokines, which are of course not licensable hence not researched. However, this would only really address the small subset of the population, who are sensitive to heavy metals and somehow can't detoxify from them as effectively as others. Autoimmune reactions, anaphylaxis and other side-effects of vaccines, some of them also resulting in encephalitis and subsequently autism, will still persist even with healthier adjuvants, due to the nature of artificially provoking the immune system, which sometimes just leads to unpredictable immune reactions, no matter what you do.

Conceivably you could work out some extended-release nanoparticle coating to mitigate this problem. But who cares about that, if manufacturers are exempt from liability anyway?

Of course with such a lunatic vaccine schedule as found in the US that has close to 100 shots, the toxic metal poison with longest half-life estimated around 7 years, accumulates so much that it is predestined to cause all sorts of neurological dysfunction. In a sane vaccine schedule, you have just 10 shots and the ability for people to opt out. Aluminium then isn't really a major priority to improve vaccine safety. There is even limited research and reason to believe that aluminium hydroxide does not cross the blood-brain barrier that much in most people. But of course the overall toxocology of aluminium is not that simple. Especially if you inject doses that are between 10 - 100 times higher than what you would naturally absorb through food.

Bottom line is we don't really know about adjuvant safety, because really no one cares, and no one does the studies. With a little bit more censorship and vaccine Lysenkoism, the profits are just rolling and keep on rolling. Anti-vaxxer science is fascist science that undermines society and harms the greater good. That's all you really need to know about.