I also primarily use a 'flip a switch' setup specifically for this reason. To be honest I think that using your own domain name is the only way to go these days

I also primarily use a 'flip a switch' setup specifically for this reason. To be honest I think that using your own domain name is the only way to go these days, as even other email providers can have issues resulting in you being completely locked out. At least with a domain name you have multiple paths for recourse or regaining access should something go wrong (domain registrar, hosting provider, DNS provider, mail provider, etc). Now that I've moved to Cloudflare Registrar, I guess in some ways I've made it harder for myself should something go wrong, since my domain and DNS are now hosted in the same place.