Both russia and the usa have stuff that can cover 20+km, This is one of the smaller ones they have plenty of, 122mm
Effective firing range15.4 km (9.6 mi)
21.9 km (13.6 mi)
(with
rocket-assisted projectile)
I doubt if the USA would bother sending a rather early gun that I think fits in with the range you mention.
A more modern Russian one 152mm that can shoot smart ammunition, uses satellites etc.
Effective firing range(OFS): 30.5 km (19mi)
(OFARS) 40 km (25mi)
The UK makes one that can have the same range with certain ammunition. All will.
That's how the arms race works.
An AlJ repprted I mentioned has moved. He is near an area that is being shelled. A Donbas city. Seems there are 2 that are critical. So far suburbs only. The Russians have taken a town 46km away. Their old mobile rocket launch stuff can reach that sort of distance. The similar rocket stuff now is up to 90km depending on the calibre used and can fire all sorts. This one is in use in Ukraine,