I'm surprised there isn't more Carlos to Mercedes talk.
Because as much as they are pushing Antonelli in F2, putting him straight into the Mercedes next year, even if he does have a good F2 season feels too much. Logan is almost certainly going to be out at Williams so Kimi goes to Williams for a year or two before going to Mercedes. And Carlos fills the gaps there for now.
Although Mercedes have dropped him from their driver academy, Paul Aron is having an amazing start to the season in F2, and it's his debut full season, after doing a couple of races last season. He'd even be more of a stop gap at Merc while Kimi Antonelli builds experience with less pressure.
Because Carlos to Mercedes makes more sense than Fernando to Mercedes. I think he would just be a headache for them.