LE 9.2 on RPi4 was a stop gap, using 32bit kernel and a franken-kodi which cross-breeded the old MMAL codec with the new GBM graphics stack. No one should be using that today
The reason we went for that was simply because the old graphics stack didn't support RPi4 and the new v4l2 decoders weren't ready yet. So we had to find some interim hack (which we knew would be throw-away) to get some release out.
64bit kernel in LE10 and now finally 64bit userspace as well in LE12 were the incremental steps we had to do to keep everything going (64bit userspace was held up because there wasn't a 64bit widevine library - which some people need for DRM stuff - available until recently).
so long,
Hias