Please define “numerous”.
Ukraine received 16 HIMARS. It is reasonable to assume that from sheer dumb luck and their heavy firepower, Russia would have taken at least a couple out by now, and at any given time a couple need significant maintenance.
Even that over-optimistic cluck Gen. Hodges says the Ukies need 3-4x. It is a very LONG front, overall.
It seems to me an answer to such modest numbers of HIMARS would be swarms of drones. Many small ones for observation, and tracking once located, bigger (but not Predator size) weaponized drones sent in for kills.
Highly mobile decoys could make the drones’ job harder.
Some Russian aircraft are still active over Ukrainian holdings or we would not see occasional vids of them getting shot down over such. Granted that fighters flying low and fast are not ideal vs. mobile ground targets.
At one time Ukraine had 16 HIMARS. There are an unspecified number more than that now.
That is besides several similar, and compatible, MLRS.
The US has at least 350 and probably more like 500.