@irdis The very latest firmware I can find for your device is https://static.tp-link.com/resources/software/2007811083558.zip released a very, very long time ago.

@Fae No, nothing like the above, It is just the SFP led that remains inactive most of the time while the device itself is working fine.

@Fae after installing this update I have Schrödinger's SFP WAN light. It turns off randomly and does not come back until I reboot however the SFP device works just fine..

Ok ..and do you have access to the adminostratove interface of at least one of the HWA routers ? do any of them have something that they call "PPPOE passthrough" or PPOE frames to switch ports ? This...

@Tolgahan No we are not. this is probably just a missing feature or a way to not complicate things under the rug.. unless the network chip inside is really dumb as there is no ambiguity between vlan...

@Tolgahan You can't use static ip, both of your providers use PPPoE ..Yes. it is non-sense, it should use IPoE instead, however many ISP (including mine unfortunately) decided to use this for FTTH...