Hi and welcome
First of all: Don't feel guilty

. I fed my old now deceased Maine Coon Iams dry almost exclusively and he lived to 15, which isn't bad.
There is lots of advice available on this forum. For instance, I learnt that grain/cereal bulking in cat food both wet and dry isn't conducive to a cat's natural digestion and 'could' cause problems with some cats over the long term.
Since then I have decided to try to feed mainly high meat/fish protein foods without cereal and mix in some raw too. I know that I just haven't got the time and inclination to go wholely raw. So I mix and match
These are the high meat content/no cereal wet foods complete:
Tesco Luxury
Hi-Life
Bozita - adored by most cats and available at zooplus website - delivered in about 3 days
Bozita
Natures Menu - available at Pets at Home
You need to check out the ingredients for cereals such as grain.
(there are others but I can't remember them)
I also feed Orijen Dry - available at zooplus
I supplement with raw: big chunks of lamb/beef/chicken wings. This is human consumption meat which I buy at supermarkets - usually the basic stuff and the discount stuff. Obviously it mustn't have a b-b-q seasoning!
I freeze it in chunks and defrost 3 or 4 pieces at a time. Cats can deal with bacteria so no probs leaving it out for them to eat though I do refigerate on hot days.