I disagree that Russia has any right to annex any part of Ukraine when Russia recognized the sovereign borders of Ukraine when Ukraine declared independence.
Crimea and Donbass belong to Ukraine regardless of any other concern.
Your take on Crimea contradicts the UN charter on civil rights. According to it, people of the land have the right to self-determination, including secession.
According to Article 9 of the Ukrainian Constitution, the above charter is a part of the Ukrainian legal system.
According to Soviet legislation, as an autonomous republic within a Soviet republic, Crimea had a right to independence from the USSR, separate from the larger republic it belonged to.
In January 1991 83% of Ukrainians voted for sovereign Crimea, independent from whatever entity.
On May 5, 1992 the declaration of independence of Crimea was adopted.
It has never become a part of Ukraine to start with after a Soviet dissolution.
In 2014 the vote was repeated with the same result.
What’s wrong with it?
As for Donbas, the official Russian position is that it is a part of Ukraine.
There are Minsk agreements though, upheld by the UN resolution and supported by the US, Germany, and France.
It details the conditions of the return of Donbas under Ukrainian jurisdiction.
That include federalization, cultural autonomy, amnesty to the rebels, and free elections.
Ukraine drags on it for 7 years because it doesn’t want Donbas people to vote.
I have no idea how they are going to reabsorb it as this point because the hatred of Ukraine is too strong after so many years in a grey zone.
They better let them go now.
The Crimea has been Russian since the time of Cathrine the Great. The Crimea belongs to Russia. Russia has it’s largest naval base in The Crimea. If you want a hot war with Russia just try taking The Crimea from it. Don’t believe me? Ask England and Turkey.