THe only ones smoking are you Manchester United fans. You got €12m for Andreas Pereira, you are apparently asking €20m for Dean Henderson. Two players that have proven absolutely nothing in their life.
You can say all you want about Memphis, but he's proven at the international stage. It;'s not like you're absolutely top class, or you're mediocre/shit. It's not black or white like that. Memphis isn't absolutely top class, as I've already stated. That's why I don't quote him at 100/200m range, which a top class player would be quoted at. He is however an attacking player, which are generally the most expensive player. He is proven on international stage. As said, he's not in the absolute top tier of players, but he is in the tier behind them. He has proven that and then €40m is a steal for a player in his prime.
Compare it to the other fees of players I mentioned, Brobbey, Bergwijn, Richarlison. I haven't mentioned Haller, who isn't half the player Memphis is who was sold for €31+4m. Nunez has all to prove and potentially goes for €100m. Raphinha has not proven anything more than Memphis, on the contrary. Yet he was transferred for €60m and he is not so much younger. Gabriel Jesus is not a better player than Memphis either and went for €50m. Adeyemi went from Salzburg to Dortmund for €40m and has all to prove. There's no guarantee at all he'll have a bigger or even the same carreer as Memphis.
In the grand scheme of this market, with the values played for all the players mentioned above it's ludicrous to suggest Memphis would be worth only €20-25m. Memphis is easily worth €50m in this market. I also don't agree he's injury prone. He's had some really nasty and unlucky injuries in the past few years. Injury prone is something else. Injury prone is like Arjen Robben or Robin van Persie who were struggling with muscle injuries all their carreer. That's not the case with Memphis.