I can see it intuitively making sense, but barring a comprehensive moral system that can argue for the value of all human life, it sems intuition is not enough. As in, it also intuitively make sense to put 10% of your income into low-yield bonds, so in case one of your family members or friends has a horrible (deadly or severely life-quality diminishing) problem you can help them.

Utilitarianism is not the only system that becomes problematic if you try to formalize it enough; the problem is that there is no comprehensive moral system that wouldn't either run into paradoxical answers, or be so vague that you'd need to fill in the missing gaps with intuition anyway.

Any decision that you make, ultimately comes down to your intuition (that is: decision-weighting systems that make use of information in your consciousness but which are not themselves consciously accessible) favoring one decision or the other. You can try to formulate explicit principles (such as utilitarianism) which explain the principles behind those intuitions, but those explicit principles are always going to only capture a part of the story, because the full decision criteria are too complex to describe.

So the answer to

So basically, I'm kinda stuck understanding under which moral presincts it actually makes sense to donate to EA charities ?

is just "the kinds where donating to EA charities makes more intuitive sense than not donating"; often people describe these kinds of moral intuitions as "utilitarian", but few people would actually endorse all of the conclusions of purely utilitarian reasoning.

(note: I don't identify as Utilitarian, so discount my answer as appropriate)

You can split the question into multiple parts:

1) should I be an altruist, who gives up resources to benefit others more than myself?

2) if so, what does "benefit" actually mean for others?

3) How can I best achieve my desires, as defined by #1 and #2?

#1 is probably not answerable using only logic - this is up to you and your preferred framework for morals and decision-making.

#2 gets to the title of your post (though the content ranges further). Do you benefit others by reducing global population? By making some existing lives more comfortable or longer (and which ones)? There's a lot more writing on this, but no clear enough answers that it can be considered solved.

#3 is the focus of E in EA - if your goals match theirs (and if you believe their methodology for measuring), then EA helps identify the most efficient ways you can use resources for these goals.

To answer your direct question - maybe! To the extent that you're pursuing topics that EA organizations are also pursuing, you should probably donate to their recommended charities rather than trying to do it yourself or going through less-measured charities.

To the extent that you care about topics they don't, don't. For instance, I also donate to local arts groups and city- and state-wide food charities, which I deeply understand are benefiting people who are already very lucky relative to global standards. If utility is fungible and there is declining utility for resources for any given recipient, this is not efficient. But I don't believe those things are smooth enough curves to overwhelm my other preferences.