@DieGar Some regional support websites are not updated regularly. This is from Argentina support portal (this FW is for the US region): So AX23 FW should not be the culprit in this case.

@Guils if they are plugged in different ports of the router, they will share the same bandwidth, so 2.5 ghz in total.

@DieGar The RE315 region should not be a problem - check this post. When the ethernet connection is unplugged the ethernet backhaul falls back to a wireless backhaul so try with another ethernet...

@Tone42 Archer C9 is an end-of-life device and if this is an issue on its FW level it's highly unlikely it would be fixed in the furure. A delay relay circuit on the router 12 V power line should...

@Based_On_Cringe This sounds pretty much expected since the wireless connection has a half-duplex nature and on every hop it halves the bandwidth - 1'st hop (14 mbps) => 2nd hop (7 mbps). You'd get...

@Val1969 If you changed your main router then you should reset RE220 to its factory defaults (press reset button for about 10 seconds) and re-configure from scratch.