I found
another old article mentioning some ATWHS from Ukraine. Just like with the other ones - not posting on the ATWHS topic because this is probably outdated (but perhaps these ideas may get revitalized at some point so I'm sharing them regardless):
Rock formations on the Dniester (mixed, transnational with Moldova). The cultural part would probably include rock monasteries and fortresses;
Scythian settlements and kurgans of the Ukrainian steppe;
Medieval fortress of Tustan. This one is still discussed, as per
this article from 2023;
Churches of Kyivan Rus' of 11th-13th centuries (transnational with Belarus and Russia). Per
this article, it would include 7 from Russia, 4 from Belarus, and 11 from Ukraine. This would cover multiple churches in Chernihiv (including the
Dormition Cathedral and the restored
Piatnytska Church), as well as St. Michael's Church in
Vydubychi Monastery (Kyiv),
Dormition Cathedral (Kaniv),
Dormition Cathedral (Volodymyr), and
St. Cyril's Church (Kyiv; part of TWHS). I assume the Belarusian part would cover the TWHS in
Hrodna and
Polatsk. The article also mentions that this idea was criticized by some as politically motivated, and now it's especially obvious that it's not happening any time soon. Theoretically, an interesting idea nonetheless - a lot of these churches wouldn't get inscribed on their own, so this kind of serial nomination would be the only way for them to get on the list (although whether they should in the first place is another question).