@thurlow885It's very poor programming by EA (nothing new there!).
The "I needed a rest and now you've not played me" rubbish I experienced a lot in Fifa 23, but I tended to ignore them, other than to reply with the response that gave the biggest boost to their morale.
The only thing about the players demanding to leave (and it's too late to prevent that with the ones that have already made the demand, which is also a stupid bug that you can't convince them to change their mind) that I can suggest is to pay attention to the contract status of players. If it goes into thumbs down and you don't address it (even if their contract has 3 or 4 years to go), it's more likely that they will demand a transfer, especially if their morale goes into dark amber 'very unhappy' (the stage above the red one).
If you fix their contract, they are less likely to demand a transfer; at least, that's what I've found in the past.