[Errno 2] No such file or directory: 'cvt'

[XK2238]

first of all, thank you for putting in the time and effort to develop this Linux alternative for the CRU

I'd like to use this to lower the monitor's refresh rate while I'm on Fedora (43, Workstation edition), but to no avail as far as I've tried:

1. running the pre-compiled appimage from releases page
2. extracting from the source code tarball
3. cloning the git repo, executing the build_appimage.sh
4. in the meantime, installing FUSE and tkinter

the first time around, the program ran with no issues, generated a config, and applied said config, but it doesn't seem to have any effect as the display remains at the original refresh rate after restarting the display manager. After that, subsequent runs of the program show this error pictured below whenever I change any value or click Generate Configuration:

any continuation on this program would be wholly appreciated 🙏 though understandable if not