The 'mail is fine' is an impending apocalypse that most people don't think too much about. Google can dump you at any time for any reason or no reason. Your chances are small, but if it happens its incredibly disruptive. I don't know the durable answer, but I definitely need to complete that step of degoogling, the job just seems huge.
Get a custom domain. Strat using that. Route to Gmail to start but easily decouple.
It took me about a year of updates but now I rarely get anything to a @gmail