The real question is what can a citizen do in a none democratic country... If you were Russian would you publically be protesting the war inside of Russia?
And all the people saying renounce citizenship, is your country gonna give him theirs ? Does Estonia offer free Estonian citizenship to Russians who abandon their's?
The real elephant in the room that I feel doesn't come up enough in these discussions is the fact that Israel is a democracy with freedom to protest etc and they are according to even holocaust survivors committing a genocide and according to mathematica and reports killing countless more civilians yet where is them being cut off from the banking system...
Or UAE in Sudan etc. Etc.
I dunno Russia is always the big boogieman seemingly...