Hovercraft troop transports are already A Thing, and a fairly significant modern use of the technology. They're mostly appropriate where there's a need to transport significant numbers of troops across flat-but-variable terrain (snow, ice, water, marsh/swamp), and where there's limited potential for enemy fire (artillery, missile, aircraft attacks).
The US have around 100 LCAC and similar vehicles, with a cargo capacity of ~60 tonnes, or 120--180 troops, each.
Hovercraft might prove useful in some cases for traversing minefields, but would be hampered by terrain (hovercraft have poor hill-climbing and slope-traversal characteristics), and might best be utilised after major combat risks are reduced, as part of de-mining operations.
I wondered about supplying troops across the Dnieper river in Kherson. The vehicle wouldn't have to stop at any point and wouldn't need a bridge or a road.
They would probably be rather more expensive and yet another thing to maintain and not carry that much. Ontop of that where would you hide them so that the opponent wouldn't concentrate effort to remove them? The more effective they were the more they would get targeted and be difficult to protect.
I really just think that nobody has tried - there probably aren't such a lot of hovercraft "on the second hand market" that can be bought and fixed up to go and the only ones in large supply are very small recreational vehicles.
They'd set off at least some kinds of mines, and also they don't do well on very uneven terrain. Beaches are fine but not so much fields pockmarked with artillery craters and crisscrossed by hedges and ditches.
I'm sure there are plenty of reasons though (perhaps noise?) for why this would be a stupid idea.