Thank you for reading. Unfortunately, mass un-subscription would be complex to achieve in Gmail. For example, the position of the unsubscribe link/button may vary from differ senders. For example, Amazon's delivery notification will be different from Medium's mail.

I am sure someone somewhere might be figuring this out.

An article I found that you might find it useful: https://www.theverge.com/2019/4/19/18411934/how-to-unsubscribe-declutter-email-inbox-gmail-outlook