it relies on US and NATO satellites for guidance,

This is a silly point, because it's just GPS. That's like saying the US is involved in every war that uses GPS technology.

and US/NATO specialists to input attacking information and flight paths

This part is also arguable. From what I understand this could be true for the M39 Block I. But it's a weaker case for the M39A1 Block I, M48 QRU, and M57 Block IA Unitary because they have GPS capabilities.

There's also a real question of what's actually stopping the US from showing the Ukrainians how to program the internal navigation systems on ATACMS missiles. Are we really gonna argue that Ukranians who had/have one of the best technical service economies in Eastern Europe that provide IT services to US/EU companies cannot program internal navigation systems because understanding dead reckoning is too hard?

If these claims are 100% true then it would stand to reason that nobody who distrusts the US would buy ATACMS from the US because they'd be fully reliant on the US to even use the systems, which would not make sense for countries like UAE, Qatar, and Morocco, given they're not full US orbiters.

US military specialists and assets directly taking part in conducting strikes on Russian territory and military facilities within Russia

This is true regardless of those specialists being in Ukraine and is simply a technical change in how war works. The biggest thing the US provides Ukraine is its spying apparatus. Ukraine literally cannot get good field intelligence on troop movements without US satellites and intelligence.

While I do agree that the US has boots on the ground in Ukraine and it is a proxy war, and that escalation is a delicate dance and the Russians certainly have a lot of leeway here as the more powerful party, a lot of their complaints are often the same thing as RTS complaints about cheesing.

Russia at the end of the day thinks that Ukraine shouldn't be able to use ATACMS because Ukraine didn't launch it's own satellites and develop their own missiles, and blah blah blah. At what point is this simply complaining that Ukraine got free weapons from the West vs an actual argument about the balance of war from a country that in practice is shooting fish in a barrel? At what point can these complaints be levied against Soviet-era stock Tochka missiles that were expended at the beginning of the war? I think Russia just found a novel way to complain about this shit and is trying to make a case. If they believed the realpolitik of it they wouldn't be talking so much, they'd be escalating with their missile strikes to make it a desperate long shot losing proposition for the West to provide continued support. In essence I think this is a diplomacy tactic where Russia is trying to keep the rules of engagement on a level that they don't feel really pressed about. In short I don't think Russia even buys its own argument.

In practice HIMARS hasn't been as much of a boon to Ukraine as US/Russia is pretending it is. They have difficulty positioning them outside of Iskander range.

In practice the US doesn't give a shit about Ukraine, the only real point that has any value is that the US is expending US capital and Ukrainian blood to play geopolitical games with Russia. But let's not pretend that Russia gives a shit about the Ukrainian blood part, it simply gives a shit that the difficulty level on its game isn't on super easy.