High CPU on PC in own infinite world

When I create my own infinite world, my cpu usage jumps to over 80% and my FPS drops below 10fps.

But when I load into my friends world which is also infinite, I have no issues at all and average over 200fps and the exact same graphics settings.

I searched for various answers but i have seen a few with a similar issue and it only seems to happen with infinite worlds of my own.

I am running the most up to date drivers for my GPU which is a RTX 2060 and my CPU which is intel i7 9th gen.