There are some players that look good in poor teams and average in better teams, and some that look less impressive and poor team but quality in better teams.
I suspect Onana falls into the latter profile, but when you consider he’s 21 - young for a traditional no 8 playing role, he’s first year in to the toughest league in Europe, in an inconsistent set up with yet another change of manager, I think overall he hasn’t done too bad.
If he’d come through the youth ranks as a 21 year old, more people may have held the same view but a price tag of £33m changes perceptions. I’d also say that with his height and leg stride, he’s better against front foot footballing teams where space is not as restricted, and less effective against two deep lying, tight banks of four.
He does need to work on the more technical aspects of his game which he would have got away with on the Continent, but pace and space afforded by the PL does not allow but hopefully this will develop in time.