X11 is not supported at all, as in I will not help you with X11 issues if there are any due to limited time and it being unmaintained itself. You can however build rog-control-center with it enabled cargo build --features x11.

Translations

You can help with translations by following https://slint.dev/releases/1.1.0/docs/slint/src/concepts/translations#translate-the-strings

Begin by copying rog-control-center/translations/en/rog-control-center.po to rog-control-center/translations/<YOUR LOCALE>/rog-control-center.po, then edit that file.

Run msgfmt rog-control-center/translations/<YOUR LOCALE>/rog-control-center.po -o rog-control-center/translations/<YOUR LOCALE>/LC_MESSAGES/rog-control-center.mo to make the binary formatted translation where <YOUR LOCALE> is changed to your translation locale.

To test you local translations run RUST_TRANSLATIONS=1 rog-control-center.