Not sure if there is an "objective" definition of hypomania, or if it just means: slightly more manic than your usual state. Like, whether my hypomania could be someone else's normal. So I'm going to ignore this part and assume that your question meant: "How to increase your energy levels?"

(The following are just my guesses; I didn't do any research.)

First, check whether you have some known problem that causes low energy, such as depression, anemia, sleep apnea, etc. Get diagnosed, use the standard solutions.

(People will recommend experimenting with drugs. I suggest caution, because of selection effect: those who survive are more likely to talk about how perfectly safe it is.)

Get fit: exercise regularly, lose weight. Get enough sleep. Eat healthy food.

Spend more time outside. Install stronger lights at home.

Remove trivial inconveniences at your home and workplace. Clean up your room. Buy things that can help you be more productive. (Buy cheap things if you merely suspect that they could make you more productive. If you think that writing things using pens of three different colors can help you, you may be right or you may be wrong, but the time you would spend thinking about it is definitely more expensive than those pens.)

Having a support group can help a lot. Try pair programming. Socialize with people who share your goals. Find an accountability buddy. Discuss your dreams with friends.

...sometimes: Do a different thing. Sometimes the problem is not you, but the thing you wanted to achieve, or the environment where you wanted to achieve it.

I would be exceedingly cautious about this line of reasoning. Hypomania tends to not be sustainable, with a tendency to either spiral into a full blown manic episode, or to exhaust itself out and lead to an eventual depressive episode. This seems to have something to do with the characteristics of the thoughts/feelings/beliefs that develop while hypomanic, the cognitive dynamics if you will. You'll tend to become increasingly overconfident and positive to the point that you will either start to lose contact with reality by ignoring evidence to the contrary of what you think is happening (because you feel like everything is awesome so it must be), or reality will hit you hard when the good things that you expect to happen, don't, and you update accordingly (often overcompensating in the process).

In that sense, it's very hard to stay "just" hypomanic. And honestly, to my knowledge, most psychiatrists are more worried about potential manic episodes than anything else in bipolar disorder, and will put you on enough antipsychotics to make you a depressed zombie to prevent them, because generally speaking the full on psychosis level manic episodes are just more dangerous for everyone involved.

Ideally, I think your mood should fit your circumstances. Hypomania often shows up as inappropriately high positive mood even in situations where it makes little sense to be so euphoric, and that should be a clear indicator of why it can be problematic.

It can be tempting to want to stay in some kind of controlled hypomania, but in reality, this isn't something that to my knowledge is doable with our current science and technology, at least for people with actual bipolar disorder. It's arguable that for individuals with normally stable mood, putting them on stimulants could have a similar effect as making them a bit hypomanic (not very confident about this though). Giving people with bipolar disorder stimulants that they don't otherwise need on the other hand is a great way to straight up induce mania, so I definitely wouldn't recommend that.

Can't check currently but IIRC there is a marked neurotoxicity cause by too much cholinergic activity during mania, leading to quicker than average dementia onset and proportional to time spent in mania. Might be controversial among specialist. Might not apply to hypomania but be a useful prior none the less. I recommend the website elicit to quickly reduce uncertainty on this question.

Edit: also related to wether putting everyone on at least a low adderall dose might be a good thing

I believe that mania does permanent damage, but everything between normal and slightly manic might be desirable. The closest factor I've found is confidence, which you build up by gradually overcoming resistances. Small, clear goals work the best, as that will give you the most experiences of victory.

I believe that a common problem for people on this forum might be their scope of perceiving the world. The bigger your scope, the smaller you will look. This is also a source of nihilism and helplessness (since our feeling of influence and the value of what's in front of us decrease as well). It's easier for fools to be confident because they compete with the people around them, and because they're unlikely to encounter a lot of people who are way above them.

If you want something truly sustainable, cultivate a "growth mindset", in which you give value to effort itself, rather than any outcome. It seems that all long-term optimization tends towards the best answer being something like "Make the best of the moment". Others might recommend "Suffer now to have fun later", but that "later" doesn't seem to come, and you might, like me, struggle to get anything done when your mood isn't good.

Another field of interest here is self-programming, with the goal of connecting with life by making things subjectively meaningful (rather than objectively valuable) if you for instance consider chores to be daily quests like in video games, there will only be advantages as long as it helps you forward. You mention nootropics, but rather than using drugs to make yourself like doing chores more, I think it's better to add value to the act of doing chores. This is theoretically entirely within our control, as the problem is not reality but only how we think about it (chores might bother us without bad weather bothering us, simply because the former is harder to accept), which means that all unpleasant feelings are technically something we choose for ourselves voluntarily.

I hope this helps, and that you take care of yourself. A final thing I want to add is that this is possible with any psychological state. You can make yourself entirely innocent, have faith in things you know are false, turn off your ability to feel stress, etc. (I know because I've managed these for shorter periods of time, weeks to months). As with enlightenment, it's nearly impossible to explain to others how to achieve it.

Thinking about the responses, I have to come to the conclusion that this is a rather bad idea. The positive symptoms which I remember very intensely just don‘t make up for the decline in critical reflection of what one is actually doing, thinking and feeling. I had suppressed that to some extent, but it is clearly a major part of what I went through. Thanks for pointing out this aspect. Personally, I will probably try to work on healthy habits, routines and stay on my medication (what I would have done anyway).

One reason I'm skeptical is the fact that people whose mood is neutral / normal are already too optimistic, a fact that significantly handicaps their rationality IMO (especially when thinking about the risks of continuing research on AI) and hypomania will make that handicap worse.

I would be more interested in making people more perfectionistic because a large fraction of our scientific inheritance was created by people high in that trait, Newton and Darwin included.

Just as almost any "is it?" headline can be answered with "no", almost any "could it" headline can be answered with "yeah probably under some circumstances".

Mental health is especially complicated in that pathologies are defined by their impairment of "normal" function and performance, for a relatively nebulous and subjective definition of "normal". Specific behaviors that might be unusual to the point of adding up to hypomania for one individual might be entirely normal for another.

IMO, you are likely to get farther by quantifying the exact symptoms you want and inquiring what induces those symptoms than by trying to redefine a relatively well-known pathology as "like that but better".