The ease with T Mobile is there too. I pay $50/month for my plan, and calls, text, and data effectively works seamlessly in ~160 countries. If I want
faster data in some of those countries, I can pay $10 extra.
Google Fi is $20/month for voice and text, plus a variable $10/month per GB up to 6GB where it caps out at $80/month.
Note that I'm not arguing against you, just wanted to clarify that the t mobile experience is just as seamless as Fi, in case I overcomplicated it.
T-Mobile even supports WiFi calling in the same way as Fi, if you want to enable it (handy for me at work, where I'm in a building built like a bunker that gets close to no reception on any network).