Thanks @Javon_ma , as if something happened over the weekend, I am now seeing speeds comparable to my test Pixel phone sitting next to the router. The result of the modem command first showed 'NO CARRIER', but then after executing only AT+QNETRC? returend
+QNETRC: "emm_cause",0
+QNETRC: "esm_cause",0
+QNETRC: "5gmm_cause",0
However, under ‘Cells info’ in the admin console it is showing connection only to LTE FDD, band 28, with no mention of 5G whatsoever (now showing 4G+ next to provider name – where previously was showing 5g NSA, and 5G cell info on band 3 I believe...).
So, I don't know what happened during the weekend, router was turned off I just turned it on in order to execute your command.... and as said, showing above 100Mbps speeds - have not touched anything... Many thanks