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.