I never doubt the quality of Kyle Walker, but I don't think Bayern Munich will sign him. If they transfer, it would be a good challenge for Walker, of course. I think he will go to Saudi Arabia to earn money because a 33-year-old football player will want to earn serious money in his last days.
At that age it's time to think about money over career and I think that's also a very natural thing for him, but if there is still an option for a better team in a more popular league I don't think Kyle Walker would be wrong to go there either. But in this case I agree more that Kyle Walker wants to consider more money than continuing his career which will eventually be released by the team that signed him at that age.
Well this is common when a player is in his old age, he will prioritize money over his career and also as we know that lately many of Europe's top players have chosen to play in the Arab League because of financial clarity they will be guaranteed there and then they will only have to enjoy their old age with finances that even exceed expectations. Meanwhile I heard that there are also several European clubs who want his services, but so far I still haven't heard about the player's decision. It was the right decision for him if he really wanted money then as you said the Arab League is the place where he can get it.
I think for some players it doesn't have to do with prioritizing money over the career. They also know that at the age of 33 onwards their physical condition won't get any better, recovery will be slower while the pressure to deliver top performances remains the same or gets even worse when you start making mistakes, become slower or miss games because of injuries. For them going to clubs where competition is less hard while earning that much money is like a life present.