We have signed Haaland and Gvardiol and Alvarez fairly recently.I think the point is that we were very good at unearthing genuine talent but that no longer seems to be the case
The only really poor signing we have made recently has been Phillips, though Nunes hasn't generally shone.
PLayers often take time to settle.
Doku Savio, Nico, Reiss, Khus,Echeverri are all very young, personally I think they may well show up to be excellent. Marmoush is hardly old.
Rodriguez, Mahrez, Bernardo, Sterling,Gundo all took quite a while to settle and they had a more settled team to adjust to.
We haven't been great this season and a little lack of planning around midfield has probably aggravated this but there is no reason to be pessimistic about our general record on player recruitment.