Sorry if anything has been mentioned I have read through all the replies yet. I'll try to address each of you points to make reading this a bit easier. Overall, going to the gym will 100% improve your current situation if you manage to stick it out anywhere between 8-12 months.
Anyone is physically able to work out, if they're able to move. With calisthenics you don't need to spend a single cent on equipment or special food specifically to work out. Though those things can help in the process, absolutely not required.
Bad genetics affect how quickly you metabolize certain micro nutrients, the (tiny variation in) speed at which specific muscles grow, the shaping and priority your body gives some muscles groups, and a few more things that are pretty negligible. Unless you inject synthol your muscle shaping can be disappointing, but never ugly
True, other illnesses and some disabilities can render people unable to progress within typical workouts.
Again, calisthenics, no gym or equipment necessary. You don't need to buy any food specifically if you actually have no money. Though most people can afford protein powder in bulk, it becomes dirt cheap. Ignore branding, ignore diet advice for the rich. Add 1 more meals if you're too skinny, and remove 1/2 meal if you're overweight.
Yeah gymbros are annoying, as are any people who've conquered a long term goal and want to share. Feels wrong to assume privilege only because they're fit, but from my situation that's just my bias talking. It takes a long time to improve your physical condition via working out, and most want to share that experience. Lot of people are on juice, a lot aren't, doesn't really matter imo.
Yeah its incredibly hard, to a lot of people its the hardest thing they will ever have to do. Difficulty is relative, the people who are fit currently may have had to go through something even more difficult than you are now. Its tough putting in pain and work to see nothing for 3 months. Its really hard.
You absolutely can if unencumbered by horrible disability. People jump to the "you're just lazy", "you don't want it enough", "you're scared to work hard" sayings because it rings true for the majority of people especially in North America and Europe. A lot of people dont find motivation with this kind of 'help', which is a huge problem in trying to assist others in the gym.
That being said, a good physique is not a cure all especially for mental issues. I can promise that spending a year trying your best will improve your situation, though that improvement doesn't guarantee you wanting to continue to live. I wasn't intending to talk down to you by any means, or to over explain any points that seem obvious. I only wanted to give information because it pertained to me, and I feel I can give some sort of value in this field. In any matter, I hope some of this could help, and I hope you stick through working out to really answer those questions for yourself.
Wow this is a long post - sorry.