I have completely stopped using google services and software on my personal devices (even have lineageos + microg on my phone. The problem is that I can't just explain to the technically uneducated people that I changed mail providers. How should I go about doing this?
I'd recommend having a tag set up for Google forwarded mail in your new account, so you can change addresses of people/companies that still use your old email address.
and alongside that, include your new mail as the reply to address, hopefully people will click for that while replying, and eventually save/use the new mail