VHF and UHF are not normally for over the horizon radio.
certainly not UHF
Many hams live for the 1%, if not 0.1%, of the time your statement isn’t true, and over-the-horizon stations come in on vhf and uhf.
It can happen with ducting. I’ve seen it in fog banks in river valleys.
It can happen with the low end of VHF frequencies. When the atmospherics are right. It rarely happens, but is more common during sunspot maximums.
Both UHF and VHF work with Moon Bounce.
But yes, UHF is almost always line of sign radio.
Linked Mountain top to mountain top repeaters were used on UHF to span between The West Coast and into Texas. Back in the 1980’s I talked to LA via a IC-2AT handheld from Las Cruces, NM. (Via the Cactus Net)
I remember when they had a space launch, Where I lived in NM, we would hear the JPL up & down link from the shuttle missions when the repeaters were not in use. It was amazing.
Turn all knobs max right to be heard. And in certain conditions, shouting into the microphone helps.