I can confirm JEM2.2x both regular and @Egnarts' responsive versions are not compatible with the upcoming Joomla! 4. Developers are working on JEM for Joomla! 4. The update on progress and deliverables will be available shortly.
I don't think there won't be an official release of JEM3 as that's going to be very confusing with the JEM3.x version that's currently around but can be wrong there. For Joomla 4 it would be nice/good to create JEM4.x so it can fully implement all the available options.
// note: current JEM3.x version was a version intended for Joomla 3.x only, but as there was decided to continue JEM2.x path that version wasn't further developed.