This is my first time trying out TeX on Guix, but ran into a problem trying to run lualatex on core-updates-frozen. Since I wasn't sure what I needed, I tried the huge full texlive package in case that solved the problem I was seeing. It did not.
Running lualatex on anything gives the output
This is LuaTeX, Version 1.13.0 (TeX Live 2021/GNU Guix)
With this lualatex.fmt file present, lualatex runs and produces the correct output. I'm guessing this is not the expected procedure, though I haven't been able to test on master to compare yet. I wasn't sure if I missed a texlive- package, but xelatex working as is makes me think not.