I used cloudflare to host a custom domain, and then use their ROBUST email routing service to, plus a send as record to essentially make my personal Gmail use an email address hosted with cloudflare. Then, I set proton mail as a recovery and use it for NOTHING but that. As close as you can get to total security with gmail as far as I am aware. If google ever shuts down my account, I just move to protonmail or MS365 and have all my stuff already linked to my domain.