I'm in a similar boat. Not so much service, but I move around internationally and change sims a lot. I dont even have a sim most of the time, I'm on wifi 99% of the time.

Don't want to pay outrageous fees for Google FI or the like, as literally all I need it for is to get into online banking (who have decided sms 2fa is now compulsory, without offering any other options like an authenticator app). I'm currently locked out of my bank, will have to fork out $50+ just to call them, then hope I can convince them I am who I say I am. Then do the dance again next year when they do it again.

Can we all just do authenticator apps?