Thanks for the suggestions. In the end I was able to solve the issue by making a copy of `libsass.so` in `usr/lib`. I did actually find a plain `libsass.so` installing `sassc` with snap (I did run `find \ -name "libsass.so"` to find out I had such a file). I think it is kind of critical to have it in `usr/lib` (at least it might be so according to [this](https://forum.nim-lang.org/t/4509#28184) forum thread).
So now the `buildcss` part goes through fine. I still have an issue when compiling frontend because of a Karax error, but I see that it is an [issue](https://github.com/pragmagic/karax/issues/138) that should not be available with a more recent Karax release (it probably is tied to 1.2, that is why in recent nimforum updates it was not caught). I will try later if this is the case and report back here.
