Mesh Paint Tool on Very Big Meshes

Hey all,

I’m finna use “Mesh Paint Tool” in Unreal Engine 5, I have a very big mesh that I’m using as a landscape (floating Island). Scale is 4km long and 3km wide. It would take almost 5 mins to get from Point, A to Point B.

When I’m trying to use Mesh Painting tool, it would lag temendously with one stroke almost as if it will kill my machine.

How should I approach this problem? I’m wondering if I should use Substance Painter but I’m not sure if it can handle a very big mesh like my island. Hoping for ya’lls help! Thanks in Advance