[Aeraaa]

10-15K makes more sense than 1300 losses. the first number corresponds to 1.8-2.7 casualties/1000 troops/day. These are normal casualties for conventional operations of high intensity (even higher than that makes sense). The official number is basically a number vs. a very weak opponent, i.e. insurgents or similar type of enemy.

Ukrainian losses are probably on that range too (maybe slightly higher or slightly lower depending on how effective Russian firepower was). Note that losses from both sides can skyrocket if a major operational disaster happens (eg. supply trains breaking down or an encirclement).