With the business they've done so far, ATM has no chance of competing for the title, and I don't think Felix values champions league football all that much; if the pay cheque is large enough, he might as well try a new challenge.
Jao Felix is a talented player and I really like his pattern of football. He's skillful with the ball, he's fast and knows when to give the accurate passes. Felix don't seem interested in moving to a new league and I know Diego Simeon pretty liked him and have always includes him in his project. Regarding to Athletico Madrid, they really need improve their squad this season only if they want to compete for the laliga title this season. Felix is among the most valuable player presently in the team and the young Portuguese have more years to play football.
Some time at the end of the previous season there were speculations of Joao Felix joining Arsenal which was a very exciting news at that time, he is very talented and plays so well and I think he would fit in well to Arteta's style of okay but the deal didn't go through but he looks happy at ATM and I don't think he will be considering leaving the club this summer.