Hi @Siddhant Jain ,
what exactly do you want to do with count or rather how do you want this information captured/displayed? You can use automation to return a count of issues matching a certain GQL. And then you can use a variable to store the size return by that JQL and finally reference that variable within the context of some issue such as placing a comment in an issue or something similar.
here is some info on the Actions in Automation.