Was looking at roughly 1k price range but could go a bit higher if the quality jumps up at a certain price point? Also watched a video on a self build with a no brand Chinese carbon frame as a bit of a project during this quarantine, but dunno if that's just asking for trouble.
For a grand I would probably look at Decathlon or Merlin's own brand. Try and get the best "rotating parts" that you can for the money (wheels, groupset) and forget about getting some top name brand. You'll enjoy it a lot more if the bike works well.