I've been trying to sell a player for several months and I can't

after the TOTY event I managed to buy 2 players that I wanted extremely much. Ronaldo and Mbappe. the problem is that I gave them 2, respectively 4 rank ups and now I can no longer sell them. nobody wants them and I've been trying to sell them for several months. the system with small ovr players who can be put in an exchange for their minimum price is very good, but at the level of the players I sell it is not profitable. i ve blocked only with those 2 players 400 million coins. please do something, because it's extremely frustrating and I'm seriously considering quitting this game because of it.