Since Gmail doesn’t block them anymore, do you have any strategy for me to stop them or should I just abandon the address I’ve had for 15 years?
The problem is, everyone knows about the myrealemail+someentropything@gmail.com trick now, and many spammers will just chop off anything after the `+`. This way, they literally can ONLY use the email you give them and they never have knowledge of your real email. You can even set it up so you can respond with that custom email.
Best of all, it's free. I've used it for years and I've caught a good few companies that have sold my email address without my consent, and this is the way they get caught because I can know for sure they sold it because I gave them a custom email that's only ever been given to them and yet I get a campaign email addressed to that email through my normal gmail.
I did this with a few gmail accounts that I created for vendors that would not permit custom domains, one of a cell company and two for a couple social media sites that did not like custom domains.
To save the existing contents of your gmail account, go into account settings and enable IMAPS access. Use an IMAP client to pull down the emails. You can use IMAP to push them up to your new provider should you wish to keep emails on a server.