Trans woman here. Your pronouns are he/him unless you’d rather be addressed with other ones. There’s multiple ways to handle exchanging them but one of the popular strategies is look at how a person is presenting, how gendered their name is, etc and if it seems pretty strongly leaning one way you can guess otherwise give your pronouns and they give theirs in return. At least that’s what I do.

answering your questions as best I can (I'm a straight male too) in order:

1. if he/him seems right to you, then your pronouns are he/him. if other pronouns seem right to you, then your pronouns are those pronouns. pronouns don't have to match up with your gender or presentation, go with whatever you vibe with
2. when meeting new people, I give my name and pronouns. "hi, my name is salarua and my pronouns are he/him." of course, it's nice to give your pronouns when asked, but other than that it's up to you
3. just including your pronouns in your profile is good. some people put them in their nicks, some in their bio or about me. if you have a Mastodon, Akkoma, Misskey, or Firefish account you can put your pronouns in your custom fields
4. you can try and figure out other people's pronouns from how other people refer to them. many people will also give their pronouns if you introduce yourself with your pronouns. it's not a faux pas to not know someone's pronouns beforehand, although I admit I don't know a non-awkward way to ask someone their pronouns
5. a good bet is to refer to people whose pronouns you don't know as they/them. if you mispronoun someone by mistake, quietly correct yourself and continue with whatever you're saying. "so after arriving at the office, he- sorry, they went to go see their supervisor about the presentation..." as long as it's not done out of malice, people don't mind being mispronouned if you acknowledge the slip-up and move on
6. I haven't met anyone irl with neopronouns either. presumably people with neopronouns would go by them if they were among people they felt safe with. unfortunately most of the world isn't safe :(

I find the use of the term guys exclusive.

Don't ask for other people to identify you, please.

Your pronouns are the ones you want to be referred to as, its that simple. So yeah, he/him if thats what you want people to use.

As for gender neutral pronouns, I just use them by default for everyone, especially on the internet when you have no idea who you are talking to as it is all anonymous (unless they have specified their pronouns in their bio/profile of course)

But overall you just get in the habit of using "they/them" unless explicitly you know their gender.

Once you get in the habit of it, it becomes more natural and you stop thinking about it.

Thats pretty much all there is to it, its quite simple and people who moan and complain about gender stuff are either:

1. Lazy, and dont want to put in the 1% of effort it requires to not be shitty

2. Really just bigoted but cant admit it out loud, so they complain about such things as a dog whistle to other bigots

3. Are extremely misinformed about what is expected of them. They seriously think the real world is out to get them, and that if they misgender someone they'll get attacked for it (in reality maybe 1 person coughs uncomfortably and they get informed as an aside awkwardly). Non zero chance these folks also think vaccines cause autism and 5G causes cancer.