Even in his prime I though one of the things with Dele was the game was (at times) too easy for him (weird thing to say at this level)
I don't think Poch could have helped (not a reflection on Poch in anyway), Dele (lot more complicated obviously) & Eriksen to me fell out of love with the game, players who rely on the brilliance/moments seem to need to love it more, Eriksen had a moment back after his heart issues where he found it for just a little bit, but has lost it again.
Unfortunately outside of some life changing event or major personal change, don't think we will ever see that Dele again.