Yeah, I made sure that it was a GSM sim card.
What ended up working was taking the sim card out, factory resetting the pixel5a, then putting the sim card back in and refreshing the republic activation again. And for some reason, it worked correctly after this. I think that why it didn’t initially work correctly was because the first time I attempted the republic activation, I typed the magic numbers into the dialer and then the republic app didn’t open and give me the permission prompts it’s supposed to – so the republic activation seemed to be stuck in a bogus state until factory resetting the phone and doing it again.
And then, of course, had to make sure turn off chat features to make messages come from the right number.
A bit of going around in circles, but got to a point where it’s working well enough until I can activate a new 5.0 plan and port my numbers to it.