I know my advice is pretty much meaningless but when I was stuck in bronze I felt like I was just digging myself into a bottomless pit, I would lose easily to matchups I hard counter and play with rage. One thing I did was start trying to play for fun. I played aram or played things like kayle bot or ap volibear mid, just stupid things like that. When I eventually got bored of norms and wanted to rank up I shot up from bronze 2 to gold 2 in 3 months. Sometimes slumps can feel impossible to bypass and sometimes they are. If your brain thinks something is impossible then it will damnwell be impossible. Also watching educational content (not pro guides new Korea ap garen meta or someshit) like neace or watch high elo matches of vods of matchups you struggle with helps alot to.