IIRC the really big damage done to Russian armour was precision heavy weaponry such as HIMARS. Drones provided targeting information. The Russians moved their armour back because it was so vulnerable,
The advantage the Russians had before Himars was supply chain and lots of ammo. But Russians never invested into systems for loading unloading etc. and they just create big stockpiles of weapons two positions that make them very easy targets, so Himars resulted in Russians trying to hide and move those stockpiles back, which makes a big difference which is observable in artillery attacks.
Also worth noting that is is Russian armour on tanks and apc's that is especially weak against manpads and drones, altough it has to be noted that most succesfull drone attacks are done with an grenade launched from an drone into an open hatch or something like that. I assume western tanks are just as easy targets if they would do that. Alltough Russia still hasn't really invested in drones. The forces with drones either funded them themselves or are part of an unit like Wagner
and whilst that means the Russians have been pushed back to a crescent on Ukraine's eastern border it still leaves the Ukrainians with the problem of how to dislodge them from heavily established defences, because otherwise the Russians can just sit there and let the war bubble away for decades. So, the imperative is for an offensive, and for that they need heavy mobile armour rather than soft skinned vehicles.
Maybe there is also a supply issue with HIMARS. After all, we don't seem to hear much about them now.
Alltough Russia has grossly overstated the amount of troops they have, they still have have the advantage in amount of troops in air and rockets. This will change when the pattriots arrive, the things they then need is long distance missiles for the Himars so they can make Russia uncomfortable on every inch of Ukrainian soil.
There is no supply issue with Himars there still being used frequently
