I don't know which Griezmann you watched but the Antoine Griezmann of Atletico was exceptional last season. Griezmann was even in the La Liga team of the season and was a candidate for the player of the season. If he feels Saudi is the best decision for him then fine. Atletico need money and they might be happy to sell, but I doubt they would want to lose Griezmann. Griezmann still wants to stay at Atletico and Atletico still want to keep Griezmann but they might sell him to balance the books if a good offer arrives.
Griezmann's biggest mistake as a footballer began when he left Atletico Madrid, because both the footballer and head coach Diego Simeone were on the same wavelength and solved a joint task very successfully. Griezmann had an exceptional season for Atletico Madrid and I probably watched a different football and championship unlike many commentators here. It's not Griezmann's problem that Atletico Madrid itself at the beginning of the season was something amorphous and characterless, which is surprising considering what kind of spirit Diego Simeone usually instills in his team.