Potential is the key word.
We’ve taken more than a few players with potential and apparently high ceilings (e.g. Ndombele) only to later regret the move.
Not to say Tel won’t come good. He hasn’t shown much yet really - but it would be unfair to judge anyone playing in a team that was very poorly organised for long stretches over the past season.
£30 or £40 million sounds a reasonable level of payment for a punt; going above that feels like a risk too far for me…but then it’s not my money.