It is too soon and also too young for Lautaro Martínez to play in the Saudi Professional League but indeed, if Lautaro Martínez accepts the offer to play in the Saudi Professional League then Lautaro Martínez will earn a very large salary. Maybe, there are also those who say it is 10 more large than his salary at Inter and yes, if Lautaro Martínez is financially focused so this offer can be accepted. But even so, I personally am not entirely sure that Lautaro Martínez will accept the offer at this moment but about Onana. It looks like maybe Onana's move will really happen at this moment because yes, Manchester United also did not extend De Gea's contract which made Manchester United need Onana to be included in Manchester United's main squad next season.
Not all players will be tempted by a high salary offer, there are also players who want a brilliant career by playing in top teams, I think Lautaro Martínez is like that, it would be a shame if he was willing to move to the Saudi Arabian league, of course his career would fade away, now he is still very young and there are still many possible possibilities in his football career and also Lautaro Martínez is currently the mainstay of Inter Milan.