What's the hardware version of your M7350? I can see DHCP server option on V3 but not V4.

Do you connect your laptop to the modem by an Ethernet cable or with wireless? You may have a try to reset the modem by pressing the reset button on the back of it for 10-15 seconds. And try another...

The RE305 and the router is still connected using 2.4G, which will be interfered by other networks. RE305 supports access point mode. This mode can make the connection and speed more stable, but it...

If disabling the wireless function, how can the extender connect to the main router?

It seems to be a printer issue. Did you test the printer with a computer directly ?

Reboot will clean the information when the issue happen. The current log has no useful information. Can you log in to the router without a reboot when the issue happen? You can perform a reset and...