In order for Ukraine to impose a tax on cryptocurrency, they must first prepare for this an appropriate legislative base regarding cryptocurrency as a whole. Ukraine is now in complete chaos and decline of the economy as a whole. They would have to deal with current problems, and they are very far from cryptocurrency taxes.
many countries experiencing economic chaos switch to using cryptocurrency. many have analyzed crypto as a solution for economic recovery. of course if it is legalized the government will make a tax law
The government may not really want to be directly involved because they feel like they will not be able to monitor the income of such company is making for them to be able to calculate proper tax, so the tactics I think they will use is to impose a very bug tax on them that will enforce them in tendering their company income for proper taxing, so they are still indirectly having control of their system without legalizing it.
Government are just too consumed with power and control that they fail to see the benefit cryptocurrency will bring directly to them if they accept it, that is why I like what some smaller countries are already doing, by embracing crypto which may make their economy boom.