You are a good cat caretaker, don’t doubt it.
Cats are pretty dang hardy creatures (except the inbred specialty ones), there’s not much going between their velvety ears, and as long as food, shelter, litter box are adequate, they will be OK.
They are just like humans, health wise it’s a roll of the genetic dice, some will live to 15 on table scraps, some will develop cancer at 1 no matter what the owner does.
To counteract “the experts”, cats evolved in tough conditions, in tough desert/ mountain terrain, hunting and scavenging, probably on the verge of starvation for their entire lives. Their natural lifespan is prob no more than 4-5 years at best in the wild, and overall lives are tough, brutish and short.
Those furry bastards do embed themselves in our hearts, but considering the above, you are probably giving the cat the best life it could have, no matter what you do (short of extreme hoarding) — warm comfy place to live safe from predators, consistent food (even the crappiest brand of dry food once a day), basic medical care. The rest is, again, depends on nothing but the genes the cat got.
Disregard the Pet Nazis — these are the same miserable souls who latched onto the masking and social distancing craze, just to feel important.