Donetsk, Luhansk, etc, did a Kosovo.
They tried to exercise their right to self-determination, just like Kosovo.
Kosovo was allowed, and NATO came along to help them fight a civil war for independence.
Donetsk and Luhansk was not allowed, and Russia of course came along to help them fight a civil war for independence.
They had a deal 2014 (Minsk agreement) that Ukraine didn't uphold.
They then finally invaded 2022, when they annexed four provinces in Eastern Ukraine.
That's a lot of restraint, given that USA had politicians (even their foreign minister) stoking the fire in Kiev when Ukraines democratically elected president was ousted in a color revolution in 2014, in favor of a new regime who wanted to join NATO.