Going to make an assumption Lew will do 22, and 23 and be gone before the 2024 season.
George will have 2 years under his belt as a team mate. Plenty of time to judge if he will make the step up to leader.
The driver I would go for will have had 5 years in his team by then and will probably be itching to go for a championship - Lando.
If Lew does a Rosberg and retires out of the blue what to do? Say he gets 8 this year and doesn't like the 22 car and calls it a day. You have George with 1 year under his belt. Assume Lando, Lec and Max are unavailable. I'd want someone with experience and speed. I'd go left field and get Gasly on a one year. Pretty sure you are getting a very different driver from the guy that did his time at RB. I think he'd be savvy enough to grab the opportunity this time around.
The big unknown is Max. If he doesn't win this year or next I bet he jumps ship.