It seems to be definitely happening this time https://joesaward.wordpress.com/2024/02/01/lewis-and-ferrari/
As someone else said, Sainz is off to Audi in 2025
ETA If we are looking at possible Merc drivers for 2025 what about Andrea Kimi Antonelli? Might be a bit soon for him, right enough. It's maybe more likely they will park him at, say, Williams for a couple of years first.