I have installed Adobe reader from the snapstore but it does not show up as an option to pick as default.
I saw an issue like this on the forum but the solution I saw did not seem applicable to this issue as it suggested running:-
pkexec nautilus which failed when I tried to run it.
For a few months now I have been using Okular to open and read PDF documents. It works great! And it will also read almost any other kind of text document.