I doubt there’s any private flights over Ukraine too. Military planes generally don’t advertise their location in combat zones

No flights at all.

About three or four civilian aircrafts were able to leave Ukraine during the war and every departure was a major military operation to undertake.

It tracks private flights too. I'm only tangentially familiar (though I have an ADS-B receiver reporting to FR24), but my understanding is that it's not required for private flight now, but more and more aircraft are being retrofitted.

Actually, it's more about airspace:

https://www.aopa.org/go-fly/aircraft-and-ownership/ads-b/whe...

"The FAA requires ADS-B Out capability in the continental United States, in the ADS-B rule airspace designated by FAR 91.225:

Class A, B, and C airspace;

Class E airspace at or above 10,000 feet msl, excluding airspace at and below 2,500 feet agl;

Within 30 nautical miles of a Class B primary airport (the Mode C veil);

Above the ceiling and within the lateral boundaries of Class B or Class C airspace up to 10,000 feet;

Class E airspace over the Gulf of Mexico, at and above 3,000 feet msl, within 12 nm of the U.S. coast."