how to stop mac from randomly maximizing screens running in the background

I'm going to apologize in advance if I sound angry or frustrated, it's because I am. I have zero idea when this started happening exactly because I struggle hard with time blindness but I know this never used to happen. I think some system upgrade within the past year(?) messed something up on my computer. While working in the past I've had windows on Safari playing livestreams for background audio while I work, and it never used to cause this issue but now the screens will randomly maximize, make themselves fullscreen, jump to the front of my page, etc. Additionally, when I try and rearrange my tabs, to make the fullscreen windows small again, and when dragging them to the sides they will automatically resize themselves and make themselves fullscreen.

I have tried EVERYTHING. I have turned off every setting I could possibly think of that could cause this. I have disabled everything I have ever been able to find record of on these forums for people struggling with either this specific issue or something similar. I have turned off drag windows to screen edges to tile, windows to menu bar to fill screen, automatically rearrange spaces based on most recent use, etc. No matter what I disable however, or whatever settings I try to adjust, it doesn't stop the problem. Background windows playing video will still automatically without being interacted with make themselves bigger/take up the full screen and will resize themselves automatically when being moved.

I feel so stupid being this frustrated about this but genuinely, it feels like it's been a year. I NEVER used to have this problem, with windows resizing themselves, this frequently or this persistently, and the fact that I've tried everything people who have previously encountered similar problems(?) have been told to do and it hasn't worked long term makes me want to explore next time I need a new computer other options entirely.

My working theory is that maybe these settings I've disabled used to work to stop this problem, and just don't anymore(?). Whoever I check my system settings after updates it doesn't show them as having been reset, and to be quite honest I haven't seen anything that's suggested that toggling these suggested settings did anything positive to stop this issue to begin with.

Genuinely, any advice would be appreciated. I just want this **** to stop. It's frustrating and it's distracting and it messes with my ability to focus when I constantly have to readjust the tabs on my computer. It feels like I've tried everything; maybe I'm stupid and am just missing something really obvious that would be an easy fix, but given I never used to have this problem before in the years I've used Apple products, I think with some system update in the past year they broke or toggled something that never used to cause any issues, and I've just been suffering since then.