The US phones won't have a working 5G here in the UK.
Also check the network bands it works on to make sure it will work properly on you network.
The deals you see don't include sales taxes, and quite often come with a carrier package.
I really doubt they would ship directly to the UK.
Even if they did, you would expect to pay export/ import charges as well
You be better off trying to find a third party company that specialises in importing and exporting electronics equipment like phones.
I always found it too much trouble importing phones sometimes, you'd need to do you homework on the retailer to make sure they operate properly