I mean, if De Gea is so that great, many teams should be interested to sign him after Manchester United not want to extend his contract, isn't? but the reality there's no big team is seriously want to sign him, Bayern Munich is a big team and they're need to find a good goalkeeper.
I think it's because of De Gea want a high salary and no team can afford it except Saudi Arabian teams.
It also makes sense when no other big team wants to sign De Gea after being released by Manchester United at the end of last season. I also thought that the barrier for other teams to bring in De Gea was his fairly large salary so that every team would think twice before actually making a decision. And Bayern Munich will also think twice about bringing De Gea into their squad if De Gea himself still has a fairly high salary. Because every team in Europe is not as rich as the team in Saudi Arabia even though it is a big team.
I'm not sure yet but I think there are two main theories for De Gea for the next season.
The first theory is to come back to Manchester United because the performance of Onana was really disappointing for this team and there is the chance for De Gea to come back.
The other theory for this player is to play in the Saudi teams and end his career there which can be good for this palyer considering his age.