Laggy Single Player Game After Switching Launchers

I've been unsuccessfully trying to earn achievements despite being logged into my outlook account in game, which I will cover elsewhere. I read online that uninstalling the game might help, so I did that. 

Since I downloaded the new launcher (I was on the old Bedrock launcher until yesterday), any world I play is so laggy it's unplayable. I've tried messing with graphics settings, turning everything down, but it's not working.

No other games are giving me a hassle. My RAM did not change between downloads, nor did anything else. I would just really like to play Minecraft and as of right now I cannot.