As of now, the most likely imo is Virginia Lieutenant Governor Winsome Sears. Sears can run on the Youngkin Administration's extremely high approval ratings in Virginia. She would also have a decent chance of winning, especially if Biden is re-elected in 2024.
Agreed, Sears has a decent shot, especially during a 2nd Biden term. Obama was also at the bottom of his approval ratings a year after winning reelection and TMac only won with 47% and the Libertarian taking more than 6% of the vote.
That said, popularity of a term-limited gov or prez isn't always transfered to the candidate of their party, so the seat could still flip back. If not 2025, I feel like 2026 is most likely going to be the year. Stratton seems well positioned to replace Pritzker. While IL doesn't have term limits, I believe he'll retire after the 2nd term.