Complex sentence: There is a tank on the square--model T-34, that is not connected with the struggles in Bieszczady but replaced a tank model T-70 that was placed there earlier, and was being used in fights agains Ukrainian Insurgent Army.
Split into simpler sentences: There is a tank on the square--model T-34. The tank is not connected with the struggles in Bieszczady but replaced a tank model T-70 that was placed there earlier, and was being used in fights agains Ukrainian Insurgent Army.