OP here. Since my original post I’ve achieved a better workaround by recompiling exiv2 with BMFF/CR3 support using the simple option in the first post in the link that darix shared:
https://bugzilla.redhat.com/show_bug.cgi?id=1979565
With the recompiled exiv2, the OBS package of darktable works fine.
That technique is specifically for RPM-based Linux distros, but I assume there must be something analogous for DEB-based distros too.
But I agree that the whole legal rigamarole around this is silly and annoying.