@Fergin When you are talking about PoE switches, you should understand, that it is much more expensive, than non-PoE. Difference between 8 and 16 port NON-poe switch is not so big, as between PoE...

Even latest hw version of TL-ER6120 doesn't have multi-net NAT feature. Now it uses Static Routing with LAN/WAN interface selection, which totally OK for the same stuff. Omada routers will have it....

Yes, you can do it. You can use gigabit RJ45 SFP module. However, you can use only fix 1G module. Not 10/100/1000 SGMII modules, as it will not work. 100M fix modules also will not work.

@TP_Link_1 @TP_Link_1 You can check it by S/N, when it was produced. Firstly, you have 2 (foreign market), then the year (20), then the month (C - November), then bla-bla-bla. So, now you know, what...

So, it definitely shows you 100M speed. What is your modem model? Check your cable also, if it has all 8 pins on the connector.

It is a worldwide situation. You can never know, what is happening in channel. Vendor can only control distributors.Usually it is about half a year for popular models.