I think as said, it is all down to what you are looking to do.
Do you NEED 5G speeds? Very very unlikely unless you are properly working on-line all the time and working on IT stuff supporting kit, managing servers, etc. - and even then if you have the right kind of setup (remote terminal configurations), high speed is not critical.
There are of course some activities that need fast Upload speeds - YouTube creators and others who might need to transfer high volumes of files from their local computer to a remote one, but for the average typical motorhomer, it is a matter of is the connection speed fast enough to stream TV or Movies and browse the internet at the same time - and you don't need 5G or even 4G speeds for that.
It's not about speed, it is about connectivity.
Will 5G give you better connectivity? no idea.
Is it worth paying extra for? depends how much really surely? If it was an extra £30, yes you would go for it. Extra £50? Maybe. Extra £100? Extra £150? £200?
But then people like to buy the muskrats Starlink and pay £99 every month to use it. To some it is worth it, but I think you really do want to have a reason to spend over £1000 per year for something that for 99% of folk will deliver no noticeable benefit or advantage. (Probably more a disadvantage as you have to setup the dishy every time you stop).
For myself, I have a 5G ready antenna fixed on the roof and a 4G router. Do I care it is not a 5G Router? Not really as 4G is fast enough for any needs I have. By the time 5G is established sufficiently to actually make it a better (better in that it delivers tangible benefits to ME over 4G), 5G routers will be a) a lot cheaper than they are at the moment and b) will almost certainly be better than they are now. And when that time comes and I still have my current setup I can just swap the router over and my antenna will be ready already.
And in my setup, I am connected 24/7 with Victrons VRM, control/monitor/configure the motorhome kit remotely, stream TV/movies/Sky, lots of web browsing and email but never lacking speed.
Obviously others have different needs and may/will have a different opinion, but evaluate your needs before deciding you must have the latest & greatest just because you can (and sometimes "because you can" is sufficient reason!)