Since the release of 1.19.7, Realms purchases on PlayStation have been failing for many users. We have an update rolling out today that should resolve this! - jhp

So you're still having issues. I purchased a realms sub on PS4 today and had my money happily taken but have not been able to use it. That was 8 hours ago. I've already put in a ticket but if reddit posts are any indication, I'm not likely to see help.