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.
if you're okay with owning a google account, then you can sign into that google account using the Aurora Store and download it there. the aurora store pulls the files from Google's repo. bearing in mind this is against google ToS so use a throwaway account; it's just for downloading apps anyway. this is the safest way i know of, it carries as much risk as using the play store.
aurora used to allow anonymous sign-ins, but that's not working at the moment. if you do want a 100% no google route, as an alternative, you could download from APKPure. it has a good reputation but the apks are uploaded by users, so there's no guarantee of safety on that front. if you go this route, you're doing so at your own risk.
on a side note, you could use the web versions of banking apps. but the website for my bank sucks. maybe yours does too lol. aurora store + signed in account is the way to go until there's a solution for anonymous logins again