Just tried Tello, sounds perfect, but the eSIM just won’t activate, since I’m not in the US today :[

That sounds awesome. I had a hardware Verizon / T-Mobile SIM and it got cancelled on me when travelling. I think on another visit to the US I got a “US Mobile” e-SIM, but I don’t think it works overseas.

It seems like there’s just no good solution that works a) forever and b) verifying every service.

Thanks for the suggestion! I think they sometimes work. They’re super clear about not promising that 2FA will work though, here’s a list of things that they don’t work with: https://www.numberbarn.com/blog/sms-notifications-from-your-bank/