Both have failed to receive 2-factor messages from providers over the years. Very occasionally the Google Voice number is blocked explicitly by the provider as a VOIP number. It's just not a reliable 100% replacement for "real" SMS in my experience.
Google Voice is close to acceptable as a replacement, and it's my primary 2-factor number when it works, but it's not 100% for reasons outside of my control.
I've heard good things, can you port a cell number in or is it strictly voip? (I haven't done anything phreaking adjacent in ages)
https://support.twilio.com/hc/en-us/articles/223179348-Porti...
I used one of their existing pool of numbers.
For inbound short-code support, you have to contact support directly and agree to a legal T&C for them to enable it.
Skype is an obvious choice, but there are many other providers.
Then you have a stable number and can read SMS via app web UI.
I switched to the same method a few years ago. It's useful even if you don't travel much, just to not tie 2FA to your phone and for not giving all those services your real number.