I will not discuss the problems experienced by Dele, but rather the character of the player's game.
Dele Alli's playing style is similar to Frank Lampard's. Dele Alli is more modern than Lampard. Of course Frank Lampard has been monitoring DA since he coached Chelsea even before he coached Chelsea. Therefore, I believe that Dele Alli will find his rhythm again under Lampard's tutelage.
It will be very synchronous for a club if a player is coached by experienced people like Lampard because at the time when Lampard was still active as a player in a club, he was also a star even though his fame may still be very little compared to other stars, but seeing this could happen to Lampard and DA, then that club would also be very profitable.
Not all good players make good coaches too. their careers are different, and indeed playing experience is important for coaches. but not everyone can be a good coach. Lampard sees good potential from Dele, he believes this player will develop much better. Lampard will probably pay attention to more young players.