I only learned about this a few years ago. Before the Cuban Missile Crisis (where Russia installed nuclear missiles in Cuba), the US installed nukes in Italy and Turkey. This made USSR very upset. Plus, the US was heavily meddling in Cuban domestic affairs. The first two paragraphs are very instructive here: https://en.wikipedia.org/wiki/Cuban_Missile_Crisis

My point: I think USSR (and Cuba) had a good reason to install those missiles. It wasn't an unprovoked action.

And as I understand it, part of the solution to the Cuban Missile Crisis involved the US quietly agreeing to abandon the placement of nukes in Turkey.

There is some analogy here for the Ukraine NATO situation.

Definitely! I think the obvious quid-pro-quo would be if Russia and Ukraine both agree to stop targeting anything behind the current front lines.

Arguably, this would even be in Russia's favor, given its manpower advantage. But Ukraine might agree to it to stop civilian terror and power infrastructure attacks.