That is correct. E.g. a 500 Mbps subscription is configured as e.g. 540 Mbps, so that overhead will not impact a speedtest.

But with a 1Gbps connection, setting 1.1Gbps might not be possible as the modems/routers can have a 1Gbps port, so there is a “hard limit” on 1 Gbps. Because of overhead, you will typically only get around 950 Mbps on a 1 Gbps connection.

As for Fast, I have seen the same thing as OP. I can get 1.1Gbps on a 1Gbps connection that normally is “limited” to 950-isj Mbps on other speedtests. The modem internally supports more than 1 Gbps, but is limited by the Ethernet-port.

Some operators (at least mine) gives the possibility to sett a different APN on the LTE modem, and this will give you a real public IP. That said, using a tunneling solution can provide better security.

From what I remember (I’m not 100% sure), my TP-Link switches has that option in the admin-interface. Model is SG108E. There are quite a few hardware revisions of these.

It is not a “full managed switch”, but what they call a “smart switch”, which have some configurable features.

What is the bottle neck you are experiencing?

Is sound like you think there is a bottle neck, but have not experienced poor performance indicating a bottle neck?