As I understood I can only count those who were subscribed from my instance but not the overall number. I do see users per month and per day but these aren't of my interest
Go to the instance the community is hosted on. Example, if i wanted to know how many subs [email protected] had i would open firefox, type https://beehaw.org/c/finance and look at the sidebar
Yes that's the subscribers from your instance.
With the link in the comment above it indicates AskLemmy has 11281 subscribers.
But I'm not aware of any method to know that from your instance or the app unfortunately.