As for wanting a guaranteed 1st rounder, this was an issue that came up last deadline, where everyone was pissed about the Clippers deal, that we should have gotten a 1st, etc., without looking at where draft picks around the league are currently sitting.
Looking at contenders, Boston doesn't have their 1st round pick this year, Brooklyn owes a 2024 1st, so can't outright trade this year, Cleveland owes theirs to Indiana, Dallas owes theirs to NY, Denver owes theirs to Charlotte, GS owes a '24 pick, so can't move this one, Clippers owe their '24 pick, Lakers don't have their pick, Milwaukee doesn't have their pick, Minnesota doesn't, Philly doesn't, Sacramento owes a '24 pick.
So out of playoff teams, you're left with Memphis, New Orleans, New York, Phoenix. So if it's a '23 pick from a contender you're after, I'd start there.