When we got DCat he was on a mix of wet and dry supermarket own cat food, eating predominantly the wet, with dry available if he's hungry between. But he has a sensitive stomach and was getting diarrhoea regularly on this. Vet ruled out anything serious and suggested diatry changes and after some trial and error, a grain free diet seems to have resolved the stomach issues.
However we've tried a few grain free wet foods and he's not massively keen on any of it. The higher meat ones he refuses to even touch and the cheapr Amazon grain free (though it might be more similar to the supermarket ones he use to eat), he licks off the gravy but leaves most of the meat.
We have found a dry food he will eat, its 70% meat content so nutritionally quite good (actually better then the wet) but I've read that feeding dry only can lead to kidney and bladder issues. I think he drinks an OK amount, not generally from his bowl but he loves sitting in the sink and licking at a dripping tap (but ignore cat fountain) and we also have a pond in the garden that I see him drinking from regularly.