I'm not so sure about forcing GTK3 being the right choice, especially because of this:

https://github.com/prusa3d/PrusaSlicer/blob/dba0377c298ab2752d2f80b5ca89d619bb984415/src/PrusaSlicer.cpp#L83-L88

#ifdef __WXGTK__
// On Linux, wxGTK has no support for Wayland, and the app crashes on
// startup if gtk3 is used. This env var has to be set explicitly to
// instruct the window manager to fall back to X server mode.
::setenv("GDK_BACKEND", "x11", /* replace */ true);
#endif

Could you please elaborate your reasoning?