Not sure I understand the support for a 5g modem on a Draytek 2927. I know I can get a 5g modem with Ethernet and plug it into the WAN2 port.

But if there's a 5G USB Dongle available (which I don't think there is), will it work at 5G speed in the USB slot (WAN5)?

I presume that the comment about no Draytek supports 5G refers to those routers than have a sim port directly in the device and not an external device such as a 5g modem with Ethernet output or a USB dongle?