Help, my roblox has lag/delays

https://reddit.com/link/1syaypi/video/5nvhkbkxbzxg1/player

I have a good computer, bought last year. This has been happening for about three weeks now. Previously, the game ran smoothly on all graphics settings, but now it lags in every game. Does anyone know what could be wrong? I apologize for my English, but I'm Polish and don't speak it well.