Hello there, @Apiuser, I do not think it is possible at all at that time. No such a setup accross all settings.
Let's make this post asking for this functionality :)

We have the "Followed Posts" Tab where it would be nice to have a check button possibility to mark/unmark the followed posts. Or having just a simple setting -> Unsubscribe from followed posts.

On the other hand I do understand this approach, as this is the only Notification system we have here. So this should go along with incorporating online notification. As you can easly forgot about post you are following after unsubscibing notification email. 

Making it short - forum developers - what you think about it? Can we have some improvements on this?

EDIT:
Is that not enough for you right now? I know it's a little annoying thing if you want to unscubscribe 100 posts, no batch functionality, but at least there is a tool to begin with.
https://ibb.co/v4tJjCF