Initially I made a floating-origin system to fix this issue. I double checked and the player is now ALWAYS within 1000 units of the origin. Still, even though the distance to the origin is never greater than 1000, visual artifacts seems to persist. The only difference is that with the floating origin system the issues start at 8 km instead of 2 km.
So this is a physics forum so I'm wondering what "visual artifacts" have to do with physics (unless you mean seeing behavioural changes) and also I'm curious as to what, if any, your question was meant to be?