I have multiple S912 devices and one S905X3. Since nightly version 20200718, including stable versions CE 9.2.4 and CE 9.2.4.1 I have had problems. The system becomes terribly slow to such an extent that CoreELEC cannot be used on a single very old S912 Acemax M12N device (year 2016 - 2/16GB - 100 Mbps - dtb: gxm_q201_2g.dtb).
Taking into consideration that after a reset the system worked fine but it became slow just at the moment the screensaver was automatically activated, I have stopped using it.
After stopping using the screensaver (screensaver used: Dim) everything seems to work fine in the last 24h..
I have the same problem with my X96 Max Plus, with the update 9.2.4.1 everything was slow, after understanding that the problem was with the HDMI-CEC I had to turn it off to use it again. I expect a brief solution to this problem.