At first glance, I thought this individual was the rare subspecies Aegithalos caudatus caudatus, the so called White-headed Long-tailed Tit which usually occurs in Scandinavia, Russia and further east to China but sometimes during migration is found in western Europe (however, usually not as far south as Kosovo).
However, for counting as a White-headed Long-tailed Tit the following features are necessary:
- a completely white head and underside,
- only the flanks may have a rosy flush,
- a clearly defined black neck and
- broad white fringes of the tertials.
Since the bird on the photos shows also rosy on the belly (4th photo) and some faint stripes on the head (3rd photo), I would say it isn't White-headed Long-tailed Tit.

Rugova Canyon, Peja, Kosovo, 28 April 2023