I use the router with sim connection as first connection and than a Ian cable connected as backup connection but disabled.
Mostly during the night it stops working, like the dhcp server stops working and the other devices don't recive the connection
I have to cheange router position without lan cable connected and it retsart to work and after i can restore the default settings.
I have already changed the router one time, so i don't think that is a hardware problem.
The router firmware is RUTX_R_00.02.03.4.