There is a non-zero chance that Miami opts out of the Watson chase because they'd rather have Tua, their high 2021/2022 draft picks, and the cap space. Not sure I'd agree but it's certainly possible. If you eliminate Miami, then I would say things tighten up a little bit. With apologies to E5, I'm about to kill a lot of cyber trees here because this stuff interests me:
#2 (Jets): Huge organizational question marks but clear favorite in terms of draft capital with #3/#23 this year and Darnold to dangle as a potential young QB option.
#4 (Falcons): Ryan in the fold and they can't really trade him without taking a huge cap hit. Julio and Ridley would obviously be attractive for any QB but rest of the roster is quite meh.
#5 (Bengals): Watson wouldn't go there and they have Burrow.
#6 (Eagles): Would clearly love to upgrade from Wentz/Hurts. Don't think Houston would be interested in Wentz and Hurts has question marks regarding how good he might be. Also in cap hell. Doesn't seem likely.
#7 (Lions): Team is a mess and currently focused on biting kneecaps. Not likely.
#8 (Panthers): Rhule seems like a decent coach and they have CMac, Moore, Anderson as a nice foundation for a QB. Upgrading from Bridgewater to Watson would make a huge impact and they can shed Bridgewater after next year for only a $5M cap hit.
#9 (Broncos): Offensive weapons on offense are actually quite good with Sutton, Jeudy, Hamler, and Gordon/Lindsay at RB. Elway is always going to be aggressive. Does Watson want to play for an inferior team in KC's division though?
#10 (Cowboys): Have stated every intention of bringing Dak back. Can't imagine this is a viable option but they're a team who has a lot of talent and obviously a strong brand for a guy like Watson to link up with.
#11 (Giants): Seem content with Daniel Jones and not the most robust roster. Barkley's presence and being on the less crappy team in the NY market might make them semi-attractive to Watson but not sure Houston would have much interest in Jones.
#12 (Niners): Tons of talent. Great QB coach. Good defense. Played in SB 1 year ago. This is a strong contender for Watson if Miami bows out.
#13 (Chargers): Herbert in the fold so not likely.
#14 (Vikings): Trading Cousins would result in huge 2021 cap hit. Have a lot of talent on offense though. Defense not nearly as good as it was in prior seasons. Probably not likely.
#15 (Patriots): Great organizational structure and coaching staff. Very good RB. Good OL. Terrible WR/TE. Decent defense that is now in flux. Lots of cap space.
So, using the assumption that Houston isn't trade Watson to someone who doesn't have a high-to-mid round 2021 pick and the assumption that Miami is standing pat, I'm left with the Jets, Panthers, Broncos, 49ers, and Cowboys as the top options. If I'm Watson, I'm ranking that group 49ers, Cowboys, Panthers, Broncos, Jets.