I have that problem with my RTX3080.
The routes load mostly okay in Surveyor, but when I'm editing my sessions or driving them, the track, splines such as roads and grass, and other objects take forever to load up. If I move to another part of the map, the issue starts all over again for that side. This makes driving and doing anything more than annoying.
I've been documenting this and will report this as a bug because you and I, among others have mentioned the same thing. This issue occurs in both versions of Plus Build 117669 and Build 118495 as well.