There is differentiation between Slav and Non Slav. Orthodox and Non Orthodox. Language alone is not annexation.Might sound harsh, but Russian culture/language in Central Asia is a national security danger for these (central asia) countries.
They have seen how Russia used the Russian-speaking populations in Ukraine to annex Crimea and create a frozen conflict in Eastern Ukraine.
The CA countries are alarmed by such development, which is why they try to quickly and forcibly promote their own language/culture.
Its the same problem that China has been facing for so many decades in SEA. ALL these countries have had their hands in blood to guard against the *possibility* of China using its diaspora to attack/influence them.
There is no solution to this for Russia. The more it intervenes and uses the protection of Russian speaking population as a pretext, the more its neighbours will try to remove Russian language/culture from their countries
They have much lower standard of living and even after investments they cannot reach Russian standards. They are depended on food and transport routes from North.
Ukraine and Belarus very different. There investments can create competing power structures. Pragmatic countries understand there limitations. but some try to become like Turkey and hang in middle. neither here nor there.