I had that bug on 19.x.x.
Try this:
echo ondemand > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
echo ondemand > /sys/devices/system/cpu/cpufreq/policy1/scaling_governor
echo 800000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq
echo 800000 > /sys/devices/system/cpu/cpufreq/policy1/scaling_min_freq
echo 25 > /sys/devices/system/cpu/cpufreq/ondemand/up_threshold
echo 10 > /sys/devices/system/cpu/cpufreq/ondemand/sampling_down_factor
echo 800000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
echo 800000 > /sys/devices/system/cpu/cpu1/cpufreq/scaling_min_freq
exit 0
That fixed it for me. I havent had random reboots since. Your milage may vary though (my guess its related to too low clock which causes memory corruption, so could be related to the actual CPU or memory banks on your unit). Note you are not alone, these settings helped other poeple (see https://forum.openwrt.org/t/openwrt-22-03-0-first-stable-release/136252/192?u=ramon
and https://forum.openwrt.org/t/openwrt-22-03-0-first-stable-release/136252/205?u=ramon)