Joao Felix is one of these guys who will probably have played for 10 different clubs at the end of his career. Don't forget that Atletico Madrid could have sold him for 150 million in 2020. His market value dropped significantly and constantly. He is too inconsistent and as you said, he is probably never worth the money that has been paid and offered for him. Maybe it will now finally work out for him when he goes back to Atletico, but there is a reason that he was allowed to leave and go to Chelsea as a loan player. Atletico paid over 120 million for him and now he is worth around 40 million.
Joao Felix inconsistency should be pointed to the fact that he has faced too much injury woes as a young player and that has affected his time entirely at Atletico. Also the pattern of football played by Diego Simeone boys is not favourable to slicky players like Felix. At Chelsea he hasn’t been injured since coming and he was certainly one of the there best players in a very poor season by the club. The reason Chelsea are opting out of buying him is that his valuation is just too much for them to handle coupled with the fact that they already have bunch of young talents already in the team and also coming in. So Felix leaving Chelsea wasn’t about his performance but this reasons.
Benzema shouldn’t be offload just like that Atleast till Real Madrid gets a new younger striker next season. With a younger striker next season along side Benzema, the team will have a proven player and also a developing one lead their attack. But selling off Benzema without having a striker that is banging in goals already would be a huge risk. Moreover Benzema isn’t too to ditched out already they just need to reduce there dependence on him by reducing his game time