Things to consider:
1. Per has more wins and podiums in the last 3 years than any free agent.
2. He is apparently good at working with Engineers on car feedback.
3. He still finished 2nd last year in WDC.
4. He won't challenge Max.
5. Anyone forget AD 2021? Fucking epic drive to contain Lewis and help deliver Max to the championship
He's definitely the safest pick. Sainz wants to win WDC and he and Max aren't best of friends. Yuki has had test laps and clearly hasn't put up a time that would make them move his seat. He's got a temper that's better, but there's no guarantee he moves into a faster car and is any better. They're also not at the stage where they care about development at least until the regs change.
Lewis is pretty honest and often pretty harsh on himself. I don't love his driving style, but he's good for the sport. He's the only driver that seems to use his platform to really stand up for anything he believes in and he's great with fans. He's kinda neutral in my book, but I think it shows that he's only really solid when he's on a team that has the best car. When his setup is on the right track he's great, but he's not the best offensive driver and not aggressive enough when he has to scrap through the pack.