Unfortunately, "throttled" does not fix the problem on these particular models. See https://github.com/erpalma/throttled/issues/255

In the meantime v2 of the patch has already been submitted, addressing some of the points mentioned in the article: https://lore.kernel.org/linux-fsdevel/904d985365a34f0787a451...

Sounds like this known issue, mentioned in the release notes:

Images for some device became too big to support a persistent overlay, causing such models to lose configuration after a reboot. If you experience this problem, please report the affected device in the forum and consider downgrading to OpenWrt 18.06 or using the Image Builder to pack a smaller custom image.