If so that could be tricky, as McLaren is in no position to know the nature of his contract with Alpine, aside from the assurances from his team/agent that he was indeed available and not beholden to any other team for next year already. Seems Alpine disagrees.
I also think that Red Bull could be an option, sticking him on AlphaTauri for a year or two before they kick Perez to the curb and then put a Piastri with Max. Or if Hamilton retires, Mercedes second seat. Most other teams I'd not mess with. Alpine seems to be a shit show now, but they're a factory team with potential vs the bottom half of the field, who are customer/sister teams. It's a better ride than anything aside from Merc/Ferrari/RB, probably roughly equivalent to McLaren long term.