In other threads, there have been discussions of the spelling of various cities in Ukraine.
To understand why there is confusion, you must understand the background. In soviet times, there was a concerted effort to Russify all the colonies. As part of this, the populaces were forced to study the Russian language (if they wanted to be employed in productive work). Similarly, documents had to have the Russian spelling used.
Russian spelling, in turn, had English transliterations.
After the breakup of the soviet union, the former colonies wanted to revert to the local names and spellings in their own languages (with the corresponding English transliterations.)
Thus, many Ukrainian cities now have Ukrainian names which are different (some only slightly so) than their Russian spellings. Whether or not a person uses or wants to use the proper Ukrainian name depends mostly on their ethnic background or the ethnic background of the woman they are married to.
Many persons in Ukraine identify strongly with Russia and are reluctant to use the proper spellings.
This reluctance is usually not found outside the country itself. For instance, most of us know that for a hundred years or more the capital of China was not spelled (by English writers) as it is now. But once the Chinese government asked that the Beijing spelling be used, it is used.
Similarly, Bombay now has a spelling that is desired by the natives and not forced on by a colonial power.
However, with Ukraine, acceptance inside the country will be slow because of so many people yearning for Russia.
The current names and populations of the largest cities in Ukraine are as follows:
Kyiv 2,660,401
Charkiv 1,464,740
Dnipropetrovsk 1,056,497
Odesa 1,077,131
Doneck 999,975
Zaporizzija 799,348
Lviv 733,728
Kryvyj Rih 696,667
Mykolaiv 509,011
Mariupol 482,440
Luhansk