We're reaching the end of an era wherein billions of dollars of investor money was shovelled into tech startups to build large user-bases, and now those companies (now monoliths) are beginning to constrict their user-bases and squeeze for every single penny they can possibly extract. Fair or not.
Now more than ever, it's important for us to step back and reconsider whether we want to be billboards for these companies anymore.
For anyone unfamiliar, some good resources to have when starting your degoogling journey are below:
Privacy Guides - A list of privacy-respecting services you can use.
Plexus - A crowdsourced information bank of service compatibility with degoogled devices.
This random PDF - A study from 2018 detailing data that Google tracks about its' users.
I typically get unlocked phones because of that. I hadn't heard about the banks, but they are typically ok as long as they are unlocked and paid for upfront.
It's not so much any of that, I think it had to do with fears of people unlocking services that carriers can charge fees for (ie mobile hotspot). Banks were worried about people somehow hacking their systems or compromising security. It all had to do with SafetyNet hardware attestation, and that Google was under increased pressure from the finance industry to guarantee software security (and in the process make rooting devices or using unauthorized ROMs damn near impossible), but I still can't for the life of me find the article.