Game crashing on load in, cannot reconnect without rebooting PC + waiting +5m, no postgame reconnect

Hello. The client has always crashed on occasion for me, but I have gotten 4 5 crashes in the last 2 days. I have done a clean reinstall and repair and neither have solved the issue. The first try the game will crash after launching, and give an error if I try to reconnect. Upon rebooting my PC, I can launch the game itself, but it's frozen as a black screen for a while, then often at 2% or 4%, for at least 5 minutes if it loads me in at all. If this happens, I also cannot reconnect postgame to give honors and must reboot the client. It happens with SR, TFT, and ARAM.

I am running Windows 10. It seems to happen randomly upon starting a game, I don't know if I can reproduce it.

It's literally unplayable, and I do not have much time to grind the event pass before the spring semester starts for me. Does anyone have any solutions? I know this has been an issue for a while, but it'd happen maybe 1/20 games, now it's every other game.

Edit: I tried to do a TFT game, crashed again, and did another clean install. Upon restarting, the client still tries to reconnect, despite it having been longer than a TFT match. I cannot play now at all.