I'm currently on the RHCSA path myself, and I can tell you that the courses are not worth the thousands that Red Hat charges. There are plenty of unofficial video courses on YouTube and Udemy and study guides and practice tests on GitHub that are free or cheap, and other resources for every individual study topic, which will be good enough.
However, though I can't speak from experience, it seems like the cert itself will look good enough on a resume to justify the investment of $500 and a month of studying.
Yeah, only thing I can think of is the few banking apps that don't have web versions.
I was lucky enough to have all my banking and 2FA apps work perfectly on GrapheneOS. The only app that gave me a significant amount of trouble was iClicker, which my school uses for attendance. That was fixed by enabling Google Play location services, and there was a (fairly expensive) alternative anyway.
I did have to buy a new phone to use Graphene, because I got my previous one as part of a carrier's cell plan, and it had a locked BIOS. Though I think the purchase was worth it, and just moving my SIM card from one device to another was enough to get it working.