This is what I do today. It works, but it's a chore I don't enjoy doing and I don't do it as much as I should.
After a while, I find managing/maintaining my filters starts to take a lot of time. And filtering is just organizing - I want to cut the noise from entering my inbox so search stays clean.
Overall, I think gmail team could do a lot more here, and I'll bet Superhuman is on it (I'm still on the waitlist).
I often use this neat alias feature in gmail for other purposes, but it doesn't work too well for me here. At signup time, I don't know who is going to be spammy, and I often forget to use it. Additionally, my standard email address is often shared when I use buttons like "Sign in with Google".
This aims to solve the problem I'm asking for. However, it's opaque how it technically works, and they seem to be mining my inbox for business intelligence and advertising data on behalf of Rakuten. You can opt-out in settings, but I don't really know what that means in terms of data flow, and the whole thing just unnerves me a bit.
This tool is promising. It's by an indie founder husband and wife team that promise to do the right thing in terms of privacy. They seem like good people, but I still feel unnerved by my whole inbox being sent to their servers for processing. Good people still make innocent mistakes, and I just don't want that lingering risk when it comes to my inbox.
At the time of writing, three Chrome extensions exist to make the process of unsubscribing easier in gmail. One does the job I'm looking for approximately, but it's closed source and the developer website is a deadlink, so I just don't have enough confidence to install any of these.