Screeb:
Aaaanyway, I disabled DSDS in the Field Test Mode menu, and 5G now works! (@MaxineN) Woo! Best part is that enabling DSDS again doesn't change that - 5G still works. So if I ever want to do the dual-SIM thing, I guess I can, without affecting 5G.
So the only thing that doesn't work still is WiFi calling - doesn't really bother me though, I never planned to use it.
WiFi Calling is only critical for me if roaming... but I suppose if I am roaming.. I am on holiday and everyone back home can wait :)
Nice to know and see a Sony phone actually do more than basic LTE....
Maybe the future is looking brighter...