Greetings,
Apologies for the delayed response.
Do you still need assistance with the HTTPS issue?
What is the current firmware version on the router?
If you navigate to Status → System, under Internal modem you can see what the firmware version of your modem is. If it is the A05 version, please follow the instructions here to update it. Known Issue With RG520NEBD Modem Firmware (Update Required)
Regarding the LAN drops, have you performed the firmware reflash via the bootloader menu as suggested? Instructions can be found here: RUTX50 Device Recovery Options - Teltonika Networks Wiki
If the bootloader didn’t help, we would need to analyse the issue further, please let me know if you have done it.
Best Regards,
Justinas