If you are really attempting to create an open-world, you should not have a complete map in a single scene (at the very least in my expertise) – with out numerous digicam rendering methods. Unity gives just a few methods to get round this want for advanced algo’s, the only being: this

Other strategies would contain ‘stitching’ I do not know if that is the technical time period, but it surely’s what I’ve used for a few years. Quick search reveals: this submit on reddit, with a ‘stitcher’ script

There are many extra methods of combating this, in all probability too many to say, however these needs to be an excellent place to begin.

I’d suggest not shopping for a brand new PC… Just analysis tried and examined strategies of loading, somewhat than dump all of it in a single scene.