Anyone who says that based off of the coincidence that kaldheim and NEO Kamigawa were both first sets, Maro stated in his podcast (one I believe about the design philosophy of crimson vow) that vow wasn't originally going to exist, and that NEO kamigawa was going to be the final set of 2021, before being pushed back with Crimson vow thrown in between. Therefore, New Capenna or heck even dominaria could have another phyrexian praetor in it.

However, Elesh Norn is being portrayed to me right now as a final raid boss who's going to stay on mirrodin, based on my belief that she was the strongest praetor, Urabrask presumably is somewhat contrarian and so unlikely to be on the side of the other praetors completely, so his presence on another plane would be a bit unlikely, imo.

This made me believe that Sheoldred had the potential to be on New Capenna, however apparently Sheoldred's kingdom was destroyed by Norn in the mirrodin novels (I can't really say, idk where to purchase or find them, btw wotc totally should provide those somewhere, it's not like they're raking in profits from not putting the ancient novels on the story website).

Btw, this is no way Elspeth's home plane, that was overrun by og phyrexians (nothing to do with the praetors, and have had no contact with the new ones. I also doubt they'll try to stir the plot by bringing Elspeth's unknown plane into being involved in the current story).

Tldr: There's no reason to wait until next year for new praetors, Sheoldred IMO is the most likely to be on another plane any time soon, Elspeth wasn't born here