I know, and respect that - it's the same with Ange for me, as I thought there was a chance he'd do what he did at Celtic and bring in some more Mitoma-profile players from Asia and unearth the academy a bit more.
We all have the capacity to get stuff wrong, which is totally human
The only thing I have issue with, on a regular basis, is when the fans are saying "Levy is incompetent if he doesn't sign playerA}and he should offer him £200k", and then if playerA doesn't work out, they say "Levy is incompetent for signing playerA and giving him £200k a week". Whether the juxtaposition be Mane and Ndombele, there's been loads over the years.
I think the club should be credited for making the transfer happen, and not criticised for it in hindsight. I don't want us to sign Tel and wasn't convinced by him in January either, but you have to back your manager even if that manager ultimately lets you down with it.
Good thing is that he seems like a good kid, even if he's no where near worth signing right now.