Our vet recommended approx 5mins per month plus 5mins (so 1month =10 min, 2month =15min etc), but this can be repeated several times per day.
I wouldn’t worry to much as you know your pup better than anyone and as long as your not going mad with things I’m sure you’ll be fine.
I think how much exercise your dog needs is a bit like the what to feed them debate in that whatever you do someone will say your doing it wrong!!