I think Richarlison has been great, but he has major major flaws. If we have a good manager who can continue to grow him as a player and remove the flaws, then hes absolutely worth keeping. If we cant, and hes just going to go down at first contact, pass poorly, etc, then as good a goalscorer as he can be, then if Brands can do his thing we are better off selling for 80 million. Brands finds the next Richarlison for 40 million, and that gives us 40 million to spend on a top striker. That then frees up the funds earmarked for summer, to resign Gomes, bring in another Digne at RB, sign a top CB, and bring in a top DM.
Sure, if we can do that without replacing him that would be ideal, but if you can replace with a similar quality player AND profit 40 million to improve the squad its a no brainer. Its all up to how good Brands is at continually identifying great talent.