My entire life, whther while i was living in Japan, Germany, or the US, the spelling of Kiev and the pronunciation of it has remained constant. I know the locals will have different spellings and pronunciations just like cities and personal names throughout the world, but this has completely changed in the West over thw last few weeks. Now its Kyiv (Keev) vs Kee-ehv.
I know this seems small or trivial, but this is extremely fishy to me.
I think that through history various places have changed names/spelling for a variety of reasons. You have provided some great examples above.
I don't see this as anything nefarious, but the change certainly signifies something. From this discussion thread, I think that the simplest and best explanation is that it is simply a change from Russian-based to Ukrainian-based spelling and (attempted) pronunciation.
The spelling change has been fully embraced by the media because it aids in the narrative of the Russian oppressor being rejected in favor of the Ukrainian oppressed.
I don't think that any more should be read into the change other than that: a subconscious-level statement of alignment.