znaf, is like the Da Flex point. You have to type mount -o remount,rw /flash to enable the writing, and then add the cgroup_enable=memory at the end of the line that already exist. After this type mount -o remount,ro /flash to put in read only again, save and reboot.
To check if is working you can use the command
systemctl status service.radarr.service (or sonarr, jackett) and look if the Memory word shows.
I recommend too reboot the device once a day to clean memory. This can be done automatically using cron.
Use crontab -e to open cron, add 30 7 * * * systemctl reboot kodi to reboot once a day at 7:30am (change the time to your liking).