Which domain would be better foobar.ai or foo-bar.com?

They want 3k for foobar.com , so im left with 2 options foo-bar.com or foobar.ai.

Domain is related to ai stuff but not 100%

.ai is a costly TLD and naturally Google places a bit higher trust on a newly registered .ai than a .com one. I see loads of .ai sites ranking lately (even for entirely non-Ai niches).

Besides foo-bar.com has a hyphen in the domain name which is frowned upon by a lot of people (and it looks ugly in general).

I'd say go for foobar.ai

I have couple of .ai domains and I would argue they work better than a .com domain with hyphen. Hyphens just make any domain difficult to type and less trustworthy