I love talking craft, so I'll answer these questions for you.
Basically, Chekhov's Gun. If there's a gun in the first act, then it has to go off in the third act. Don't put anything in that is irrelevant because it bogs down the story and it creates expectations for its use by the viewer. So if being gay has no relevance to the plot, motivation, action, or whatever, just hold on to that information until such time that it becomes relevant. Having a gay boyfriend doesn't mean anything if this boyfriend isn't a character or familiar to the viewer. It's okay for them to be gay and it not be drawn attention to - you just don't write anything that would indicate otherwise. Then, when it becomes important (because being gay is an obstacle, a motivation, or a solution), you can draw attention to it without it feeling like a surprising reveal or an unnecessary bullet point on a list of character attributes.
It's the thing where you have to describe a character without mentioning their job or what they are wearing. If you can only describe a character as 'gay' but can't describe anything else about why that matters, then you've created a stereotype, not a character (much less a gay one).
I've been watching Xabungle, an early 80s giant robot anime made for children, and it's got a surprising amount of nudity in it. There's toplessness is every other episode. Apparently, this was not a problem for children 40 years ago, but we can't even handle that as adults today. If you really want to be blown away, check out Ms. Machiko. Also an anime for children with tons of nudity.
So I think it is a pretty weird idea that there is a wrong way to sexualize a female character because it's obvious that there are societies out there that do not have the same hang ups that we do about it. This means that it is not the act itself which is wrong, but the viewpoints of those judging the act.
However, as a writer, you never want to make something gratuitous (unless gratuitous is your goal - a valid decision). Basically, every work you create has a purpose. Some idea or story that you are trying to convey, and something that is gratuitous draws attention away from the purpose of the work (in the same way as described above with Chekhov's Gun). You have to know when and where to use things so that they enhance a work rather than drown it, and I think Xabungle has been rather illuminating to me in that it absolutely doesn't do this, even though you would think that topless nudity doesn't really have a place in children's giant robot anime. It ultimately doesn't come across as excessive because it is appropriately used - Xabungle is a comedy (and a parody) and it turns out that nudity can be very funny, dramatic, or satirical.
If I were going into a work with the intention of creating a gay character, I would first try to figure out how being gay informs his motivations and personality. Is it an obstacle for advancement? Does he love a character who can't love him back? Is he doing something for the purposes of showing off to another character? In all honesty, I'd probably make his main motivation being his sexuality, but I wouldn't draw attention directly to it (similar to Renly in Game of Thrones) so that the people who are paying attention would be rewarded with a deeper understanding of the character.
Within the world of Apex Legends, there's not much I can think of where it would matter. That's not to say that it couldn't matter. Perhaps there will be some element of plot in the season passes that could make use of this character trait. But since it isn't there yet, I would keep it in my back pocket for the time being. As the writer, I would be aware of him being gay, but I'd also have inside knowledge of a whole host of things that make up his character that the audience just wouldn't care about or would draw the wrong conclusions from. It's my job to put those things into the work where applicable in a way that enhances the work.