Toprak Razgatlioglu managed to win the 2021 World Superbike Championship. Toprak has a contract with Yamaha until the end of 2023. Toprak says he will move on to the MotoGP World Championship if he joins the factory team. For this, Quartararo's deal should not be extended. Toprak is a very talented person and Quartararo may not be signed for this.
In terms of talent, I think Fabio Quartararo is more dominant because he came from Moto3, Moto2 and then to MotoGP with a contract in the satellite team and was able to become Rookie Of The Year at that time before being signed by the Yamaha factory.
Now for Toprak Razgatlioglu who is in WSBK now, I think it will be more difficult when he moves to MotoGP even though he was a WSBK world champion last season with Yamaha, but considering that in the past there were several WSBK riders who moved to MotoGP, they did not experience an increase in performance as expected by the team, then this can also happen to Toprak Razgatlioglu if he moves to MotoGP even though each rider has a different way of driving and a different character in racing.
And the goal of the Yamaha factory itself is to keep Fabio Quartararo for the next few seasons, but if this doesn't work for Yamaha, then instead it is to bring Toprak Razgatlioglu to MotoGP instead.