He's not getting his shot until at least late 2022. So he'll be waiting at least a year. He cannot fight Parker like initially thought because Parker though a rematch with Chisora was more important. Parker doesn't deserve a shot IMO. Who should he fight in the mean time to keep himself active?
I personally think Ortiz would be an interesting fight. Realistically it's the best offer Ortiz will get at this age. If Ortiz wins he becomes a mandatory challenger, or at least gets a decent chunk of money to fight a mandatory challenger.
Ortiz would be my first choice. We all know Joyce has a good chin, but how good is it really, Ortiz would definitely test it like never before. If Joyce can walk through Ortiz's counters and break him down faster than Wilder then it makes a statement. I think this is the most doable fight as nobody else has been proposed as a likely Ortiz opponent. Ruiz Jr would be my 2nd choice but it looks like he's fighting Martin instead of Ortiz which was talked about at the start of the year. But if that doesn't happen and Ortiz doesn't want to get in the path of The Juggernaut then this fight would be a good 2nd option. The winner of Whyte/Wallin would be my 3rd choice but whoever wins this is WBC mandatory so I doubt they'll risk it but you never know, Whyte's a risk taker but after what happened with Povetkin he might decide to just sit on his mandatory status if he wins. The winner of Kownacki/Helenius would be another option, not the best but one that would interest some fans. I could see Joyce winning convincingly against either fighter.
It would be interesting because Ortiz is a great boxer and will outbox Joyce, and is a step up from Takam, and Joyce will have to outlast him, which he will, and KO him late.