Background-Marzipan8

It cuts down a lot of BS on the phone support lines when you use the correct terms and can have a sensible go at diagnosing the issue.

We dont use the CPE term often in the UK. It's modem ONT router etc.

Have a look on www.bidb.uk and see what comes up.

Go for 3. It's a pain to get out of CGNAT on EE

Change the APN to 3internet on whatever board / modem you use and that should see you right for failover. I'm not sure you to config that on your particular HW though.

Right ????

I think the easiest thing to do would get a used 5G hub from the likes of fleabay, setup the BSD box for link fail over. What distro are you using ?

For double NAT issue getting a real IPV4 address is a chew using regular data Sims. The only one I've had long term success with is 3.

Sorry, I'm assuming your UK based ?

Your just pissing cash in the wind buying ancient HW like that. Why are you so keen to get WRT ?

That's not a bad speed for copper tbh. Have a look on www.bidb.uk and see what comes up. If you need any advice just holla at us.

I think a previous openreach enginner has disconnected all the extensions when that face plate was put on.

It's quite common and reduces all the interference that screws with the broadband. Be warded if you move the router you will be in for a speed drop. Ideally you leave the router at the master socket and run ethernet to the PS.

ONT traffic is shared with you and the neighbours but it's encrypted in transit. The OLT won't be having any of your shenanigans unless it's provioned at the ISP side. ( Very unlikely )

For the sake of convenience and troubleshooting go all in on one brand. Mix and match might save you cash now but waste time in the future.

Omada is well priced and solid hardware. As others have mentioned the ER605 might cap out. The ER7206 might work better in the long term.

I don't think such a thing exists but teltonika gets quite close. I'm also interested in such a thing.

If your dead set on Unifi go nuts. But at least check out Omada.

Don't be making expensive descions on a complete network stack just because it looks pretty.