The difference is that Crimea had some voting about annexation in 2014, there are some legal documents in which Russia recognizes Crimea as its part, and Russia has full control of it, while for the rest of Ukraine territories, they are under occupation, not recognized by Russia also, it is ongoing war.

Crimea and Kosovo are the similar things. Legally, Kosovo is part of Serbia, it is not recognized as separate country by UN and majority of the countries, however, it is mapped as separate country. Why? On the ground situation is that this part of Serbia has its own self claimed separatist administration. That is why Crimea can be mapped as part of Russia, while other territories of Ukraine cant. It is who controls them administratively. Claiming and disputing are present all arround the world. 