The only attractive thing about Merc is that they did once nail a new engine regulation and subsequently dominated. I'm not sure Alonso even wants to take the gamble on them repeating that, and everything else about them currently doesn't inspire confidence. They've clearly struggled to understand the current regulations, and three years in a row with constant grave correlation errors is a huge red flag.

As for RBR, they probably aren't interested, honestly. They don't want someone challenging Max, they just want a stable number two. If anything, they'd also probably want someone younger than Checo to hopefully have a stable nr.2 for the rest of the duration of Max's contract.

Also, I'm not even sure Alonso would want to go there. I think he knows Max is better than him, and I don't think he would want to go there and be consistently beaten. He needs to luck into a car that is better than Max's, and of the options open Aston is really the best. They'll be a Honda works team for 2026 and Honda is the reigning constructors champions' engine provider. That's got to be the year he's essentially gambling on with this contract.