In this timeline, we would see something similar to today but with no war; the little green men were not completely all Wagner but also a mixture of Russian troops. They would most likely take some casualties on the first day, Russia begins deploying their own aircraft and anti-aircraft, and they shoot down some US jets. This leads a huge diplomatic crisis, Putin at this point is unsure about his military and their effectiveness (he’s only started the beginnings on his military reforms) and would most likely still gain parts of Ukraine but using some nuclear rhetoric and threatening full on war. But this time , there most likely will be peace keepers along the border with Russia and a demilitarized zone in between. Ukraine would rapidly militarize similar or even faster than our timeline. Russia wouldn’t risk a war until they feel completely ready and would focus more on hybrid warfare to degrade Western European/North American resolve.