Their deployment could be used as part of some future deal with Russia but they're creating insecurity in the meantime
Today, the Russian government has neither the intention nor the capability to launch the sort of premeditated conventional attack on NATO that the new missiles are supposed to counter. Russian nuclear "saber-rattling" is intended to deter NATO from intervening directly in Ukraine, and thereby starting a NATO-Russia war. There remains however an acute risk that an unplanned mutual escalation could lead to war. In this case, U.S. missiles firing into Russia from Germany could easily be the tripwire for nuclear catastrophe.
Russia not blocking Ukraine NATO and EU membership
a true independent Donbas and Crimea administered by the UN for 2 years, followed by UN observed free elections resulting in self government while retaining UN security presence. After an additional 8 years, UN will allow membership, withdrawl its security forces (unless asked to stay by the host nation), and each nation can freely apply for EU, BRICS, or other associations as their people desire. Ukraine and Russia agree to not accept either as provinces for 30 years.
a full Russian military withdrawl and demilitarization of both Donbas and Crimea
return of Ukraine held Russian territory and Ukrainian withdrawal from the Donbas
agreement to build a new NATO / Russia arms reduction treaty within 2 years with teeth for withdrawling.
Russia agrees to not annex territory for 20 years.
Putin stepping down as President.
While both sides would lose a lot form their goals of the war, it could be potentially acceptable to both sides.
Otherwise I just see this continuing to escalate until Moscow falls or nukes are dropped.
I get that you're making some weird comparison to Iraq and Afghanistan, but who besides the world itself would be the colonizer in my recommended arrangement? The world itself in my recommended United Nation governance followed by a local government chosen by their own legitimate referendums with international observers and gun free polls? Is that not better than Russia just claiming them with no say by the people (unless you believe the sham referendums under armed watch im a war zone as legitimate)?