were there any pre canon concepts for adrien's/felix's room? i hate the canon one so much the layout confuses me

Afraid not. I think the closest we have is the information that Felix/ Adrian's family owned a hotel (this is before he was made into the villain's son.) A lot of early and even current ladybug is pretty focused around Marinette. Nathan-Felix-Adrien as a character is shockingly inconsequential to the narrative as a whole. (Which is probably why he was so easily edited throughout development whereas Marinette stayed pretty consistent.... And is also apparently still the case from what I've heard of the recent season.)

You can actually really see a lot of the inspiration that it transferred to the agreste mansion... But it also lost a lot of style and flair. Richard had a lot of art deco inspiration in the buildings associated with his character. And you can kind of see that in the hotel piece here. It's all connected, at least I believe it is.

It makes sense that the current one is frustrating. It's a mix between " oh this is what a fabulously wealthy teen boy would like" being full of video games and literal arcade machines, but still having like no personality? Like it's big. Because Adrian is rich. And it's like... Largely undecorated because Gabriel is like a minimalist or whatever... Except for all of the stuff that Adrian has because he's rich. And that's literally the end of it.

Edit: If I were to fathom a... A room that does line up with that hotel era then I would do something like this, except with more whites and golds rather than blue... Or just tailor it to however the cat's relationship to his father is.