The Germans did accept some Ukrainians into the German Army. The Waffen SS 14th "Galizien" Divison (later 1st Ukrainian National Army Division).
To do this, you would need to have someone other Hitler in charge. Hitler and the top echelon of the Nazis wanted to exterminate the Slavs and use the land for Lebensraum. Let's say someone like Rommel is in charge. A military leader, a guy who isn't going after Jews and Slavs. This leader would in an alt war with the USSR would certainly arm the Ukrainians and Batic Peoples. IOTL Stepan Bandera did declare Ukrainian Independence in L'viv in 1941. However the Gestapo sent him and many others into a concentration camp for political prisoners right afterword. If we are going with a different leader of Germany but assume war on a similar time frame as OTL, (totally hypothetical) then Germany would likely assist in the declaration of an independent Ukrainian state. This new state would probably be led by either faction of the OUN, though more than likely the OUN-B/R of Stepan Bandera. This state would immediately be attempting to create an army to assist in the liberation of the rest of Soviet occupied Ukraine. They would probably consist of many of IOTL's Ukrainian Insurgent Army members. Without Hitler the war and all of Europe is so immediately different that its impossible to say what would happen.
If we just go semi-ASB and have Hitler not think Slavs are sub-human because he grows a few more brain cells (for the sake of answering the question as realistically butterflies would abound), then we could realistically still see a Soviet Victory though it becomes far less likely. IOTL Millions of Ukrainians died under the Soviet Banner. ITTL They'll be fighting under an independent Ukrainian State. Some will still fight for the Soviets but defections would fairly quickly cause massive problems for Ukrainian Red Army units. Germany IOTL occupied most of Ukraine so ITTL an independent Ukraine takes control of most of that territory. They'll meet some resistance but nothing close to what the Germans IOTL met. They'll soon have many more divisions (likely armed with captured Soviet equipment) and with any luck will be able to reach the industrialized Donbass before the Russians can take or destroy many of the industrial facilities. Once that occurs Ukraine can produce its own weapons though getting the materials to produce their own T-34s etc. unfortunately is not likely as far as I can see, before the end of the war. I don't think a Soviet Victory is likely though it is certainly possible. Volgohrad might fall much faster which almost guarantees a Soviet defeat.