So in BL games, the player can choose which route to take right away instead of making choices that lead to a specific route? There are no other choices besides choosing a route and an ending? It seems pretty straightforward! The protagonist having their own personality seems interesting, but if the plot always relies on sex, I might not like it very much... If I end up playing BL, I'd like to try something lighter, haha. I already feel awkward and embarrassed when something sexual happens in otome games, so I think my reaction would be the same in BL games, so for now I don't see myself playing something like that!
It's not that straifghtforward. Sometimes, to end up on a route, you just need to click on 1 choice but its not in a format like "ill chose X route" or "ill chose Y route", but something more like "agree/listen to Y" or "agree/listen to X", if you see what i mean. But also, sometimes you have a few small choices to pick in the common route, and once you reach the end of the common route the game will analyze for which character you picked the most answers. Like, if you picked 3 answers that are X leading but 5 that are Y leading, then youll end up in Y route. For the endings, its the same : either you have 1 choice to make, or several choices that will lead to one ending or another. Sometimes, theres also choices which matter more than others for both the route choice and the ending choice.
Sex is part of the plot, but it doesnt necessarily rely on that. I recently played a very long BL game in which sex scenes were indeed important for the story, but were like 1% of the route. Some BL games are very sex centered tho, with a lot of sex scenes. Also, you need to keep in mind that a lot of r18 BL games have scenes of noncon, which can vary in intensity/violence/coercion.
Also, for the most popular BL titles usually theres a PSP/switch version in which there is no sex. For example, there is for Dramatical Murder, Togainu no Chi, Luckydog1,... Maybe you can look for this if you want to play popular BL games without the hentai scenes. But also, you need to keep in mind that those titles were titles rated 18+ at the beginning, so the hentai scenes were meant to be part of the story. So, without them, you can feel that its lacking something and some character development is lost. For ex, i played the og r18 Luckydog1 one, and then i played the switch version later. The switch version didnt replace the hentai scenes with other scenes (or very rarely), but just deleted them. So there is less content, and sometimes it can lead in some misunderstandings character-wise.
SO if you want to play BL games but dont want sex scenes, you can either pick a BL game which isnt rated 18+, or you can play the non r18 version of an original r18 title. But if you pick the second option, id advise you to look online if the non r18 version is worth playing or not.