For some more background, see also https://github.com/lxqt/lxqt-session/pull/278 (which is the pull request where it was discussed whether or not to set SAL_USE_VCLPLUGIN=qt5 in upstream LxQt).
Short summary:
SAL_USE_VCLPLUGIN=qt5 by itself isn't tested upstream and definitely experimental. If you really want to use it, set SAL_VCL_QT5_USE_CAIRO=1 in addition, which *should* probably work pretty well (mostly like the "kf5" plugin, which is used by default on Plasma and LXQt according to LibreOffice's default selection mechanism), but is also not tested/used by upstream.
For some more background, see also https:/ /github. com/lxqt/ lxqt-session/ pull/278 (which is the pull request where it was discussed whether or not to set SAL_USE_ VCLPLUGIN= qt5 in upstream LxQt).
Short summary: VCLPLUGIN= qt5 by itself isn't tested upstream and definitely experimental. If you really want to use it, set SAL_VCL_ QT5_USE_ CAIRO=1 in addition, which *should* probably work pretty well (mostly like the "kf5" plugin, which is used by default on Plasma and LXQt according to LibreOffice's default selection mechanism), but is also not tested/used by upstream.
SAL_USE_