Meh, these "before - after" pictures are always completely useless when not done in a comparable pose. Of course a picture of him with no body tension at all will look thinner than one were he is throwing his arms up in the air. Biceps will always look way bigger when your arms are lifted backwards bent over your head. And facial analysis based on in-game pictures? We should probably conclude that Phil Jones is eating babys because he's looking like an Uruk Hai in certain situations.
I mean, I'm the biggest Bayern hater there is but I find it very doutbful that they tell one of their players to take steroids in a short mid-season window given all the side effects. Football is not American football, bulking up to no ends does not have benefits, every muscle mass a midfielder needs can be soundly achieved through normal training.
This is from a year ago btw:
I guess his steroids source dried up until Corona? EPO is the big thing in football, that I'm sure of. Stereoids? I don't really think so...