Ranked keeps kicking me

Starting yesterday I’ve been getting disconnected from ranked matches, about 1 out of every 3-4 games I play I freeze and then get kicked for being “disconnected from server”. I’m plat 1 and was almost at diamond, and every time I get kicked I get -45 for the entry fee, -45 for an abandon fee and a 10 minute delay. I’m pretty certain it’s not my WiFi because I play with my brother who is in the same house, with the same setup as me and he can play just fine, but I get disconnected from the same match he’s in. Our party chat never lags either and I can play regular trios just fine with no problem, but I keep getting kicked from ranked games and smacked with the penalty. With only two days left it’s making it hard to get to diamond when every third game is an automatic -90RP, even if I’m in the game with +100, if I get kicked it’s instant -90.