Would you upgrade fro 1080ti to 2080ti?

Unless you've got some deep ass pockets, I wouldn't bother upgrading from a 1080ti to a 2080ti unless you're maybe running a 4k setup or something of that sort. Honestly though, the 1080ti could handle that quite well regardless, and you'd be better off waiting unless the next series or two before upgrading if you were good with cash. Just my two cents.