I think that Paolo Bacchilega is going to spin a new file-roller quickfix release in a few hours.
This release would wire up the new (and now free) libarchive support for RAR files to File-roller. It would be nice to be able to use that new libarchive feature in file-roller, the proper libs (libarchive and gnome-autoar) are already shipped in Hirsute.
Not much code has changed, it is rather a thing of stopping marking RARs as unsupported. And RAR files are pretty ubiquitous in the net. It would be nice to have support for it shipped OOTB.
Maybe a small distropatch would be easier to sneak in at this point.
EDIT: There is a 3.39.1 release for now: https://gitlab.gnome.org/GNOME/file-roller/-/commit/18cba7d2d5d89a66ec4361a7584117d802e74e7d
EDIT2: And a 3.38.1 one btw, but without that fix: https://gitlab.gnome.org/GNOME/file-roller/-/commit/12d6c77fb736d70bee4c8f6f5ea7c60adde8473c
EDIT3: That would be the Nautilus side of the rar enablement (just RAR added to the MIME list): https://gitlab.gnome.org/GNOME/nautilus/-/commit/c839b586dea508cb5cb292b8494b3e6b83733524