DaveE I completely agree.
An example, with my phone. When I first got a 4G phone I was getting great speeds but then very quickly it started to grind to a halt.
I then turned off 4G and went back to 3G and got faster speeds.
This was due to the 4G network not being robust enough and as everyone got new phones and turned them on they were pre-set to 4G and nothing else. So the 3G network was freed up and the 4G network swamped.
I'm now back on 4G as the infrastructure is much better. The same, I'm sure, will happen for 5G. Only advantage now, phones tend to scan for the fastest speed available from the options it can pick up and use that (I know my iPhone does) where they didn't do that in the past. So my phone regularly swaps from 5 to 4 to 3G depending on where and current network density.
5G is probably great right now as the new phones are only just starting to roll out but it won't be long till the majority people will have a 5G device in their pocket. Then it's a waiting game for the actual network to catch up.
I won't be upgrading to 5G for a while. The price of the hardware is still to high, even though it looks like my caravan site does have signal. Worst case, I could hotspot 5G off of my phone for the time being. Linkback: https://staticforum.co.uk/index.php/topic,683.msg1667.html#msg1667