This works great when launching libreoffice from terminal / launcher, however when opening a file directly within nautilus, that env is never picked up and you get the “basic” UI. I’ve tried setting that env in many places that could be read, but so far I didn’t find any file located outside $HOME (so all appvms based on this template get to work without further changes) that could make it work.
Only workaround I found is to place the env directly at libreoffice executable, with the downside that once the file is replaced due to an update you’d need to change it again, but so far is the only one to make it work in all places (terminal/launcher/nautilus)
/usr/bin/soffice
put the export just before the last exec line
export SAL_USE_VCLPLUGIN=kf5
# oosplash does the rest: forcing pages in, javaldx etc. are
exec $RRCHECK $VALGRINDCHECK $STRACECHECK "$sd_prog/oosplash" "$@"