I'm going to make an incredibly simple list with very little nuance, because the reality is that so long as you don't buy a total POS, the gun you buy matters far less than your training. So I'm keeping it very straightforward.

As someone who loves unique guns and much as it pains me to say it, it's hard to go wrong with your basic Glock. They come in all shapes and sizes and calibers, and are the default choice for a lot of reasons.

Get something in 9mm. Ignore anyone who says otherwise. Dozens of studies have shown that with quality defensive ammo, it's going to do it's job.

I'd recommend a Glock 19. Lots of rounds, fairly easy to carry, nor particularly heavy, and a very popular carry gun all around. If you find that too big, you can step down to a 43, but you're trading shooting comfort and capacity for daily carry comfort. Not necessarily a bad thing if it means you're more willing to carry it. New, you're looking $400-500 depending on seller and generation, but law enforcement trade-ins aren't a bad idea if you're on a budget. They're usually well taken care of and have very low round counts.

For accessories, have at least 4-5 spare, high quality magazines. There are some very cheap ones out there, and a shitty magazine can turn the best gun into an unreliable one very easily. Even if you don't plan on concealed carrying initially, plan to get a good AIWB (appendix in waistband) holster. Probably about $100-150 max.

Night sights aren't a bad idea, but not necessary.

Only other thing some people will add is a light, but again, not a necessity.

A small safe that can be bolted down is a good idea. Don't have to get too fancy with it, just something that prevents an opportunistic grab or some nosy visitor from fucking with it. Maybe $200

Ammo. Buy lots and practice lots. It'll sound like a lot, but 500 rounds/year is kind of what I aim for. It's only 5 range trips with 2 boxes of ammo each trip. Find a local club/range (most are shockingly LGBT friendly, at least in blue-ish areas. Regularly practice with whatever defensive ammo you pick, but you won't want to practice solely with that unless you have a LOT of money lol. My personal pick are Federal HSTs. Very well rated, reasonably priced, lots of testing showing they perform well, and not a meme like a lot of "defensive" ammo seems to be. Keep at least 100 rounds of it on hand, but more is always better if possible.

As for the ethical consumption, unfortunately, given we're talking literal arms dealers here, you're kind of limited... Buying used helps, but only so much. Glock is Austrian and Federal is a subsidiary of a Czech company, so even though the manufacturing is in the US, you're not directly supporting dictatorships like with buying something made by Canik (Turkish) or something.