It makes perfect sense for Abu Dhabi to invest in a PL club, i.e. it's perfectly logical.
It doesn't make much sense to turn a 100m player into a bench warmer, though. None of those speculating about Neymar doesn't say what happens to Grealish if we sign Neymar. They don't seem to realise that Pep is not going to give up on Grealish or Foden before the start of the season! How do we fit them in the team?
Now, if we have promised Bernardo that we would let him go if Barca paid say 70m, and if Barca find the money, then we are likely to look for a big name midfielder or attacker, say Bellingham or Neymar. If Bernie goes and Neymar comes, then I guess Pep will try Foden or Grealish in midfield. Pep won't give up on Grealish before giving him enough chances to win a place in the starting XI even if Neymar arrives.