If Germany had won the home Euro, it would have been an excellent end to Müller’s career and for Kroos as well, Spain was luckier, they will remember this hand ball play for a long time, but nothing can be changed. Probably only Germany could stop such a Spain... Yes, Müller will spend several more seasons in the Bundesliga without any problems, but it is clear that he is no longer as good as before, he will probably play as long as the coach gives him such an opportunity, and when he starts spending too much time on the bench then decide to end his career.
One of Germany’s most decorated footballer this is certainly the right time to give youth the chance to showcase their talents. I don’t think any of the current or active German players have the stats that this man has in international games for Germany. Golden boot winner at the World Cup, youngest teenager to do it then, numerous golden both runners up. There wasn’t a Germany world without the spectaculars from Thomas muller. He is surely retiring in high, and he left German with a worthy replacement in person of Jamal Musiala.
As for club football I think he wouldn’t also go past his current contract with Bayern Munich, even if he intends to continue playing football it might be outside the club he has spent his entire years at. And I don’t think Muller will be playing for another European club aside the Bavarians. He might wants to explore outside Europe too but I doubt. So the club football ending might be here too sooner or later