Seeing as the Soviet Union would like adopt a MG42 variant (it was so effective the successor MG3 is used until today!) I think the Soviet Version would look like this ^
Above is a Yugoslav M53, their own version, and the modifications done to the Soviet Version will likely be similar to that of the Yugoslav version given similar schools of thoughts in terms of armament.
The STG 44 will likely also be produced in the Soviet Union as well, given in this timeline Hitler is willing to give away rocketry tech and jet engines, he will certainly give light arm designs away. It OTL arrived to late to really have any notable effect on the war, but this war continues longer (not notably longer but long enough for much more of these weapons to be mass produced in Soviet factories) and Soviet mass production will greatly increase its use.
Edit: adding @cortz#9 photo, as it is simply too great to leave out. Will be interesting to see how this tank will evolve further in Democratic Russia or perhaps influence that of its opponents further. Tanks will be bigger than OTL for sure!
Also this photo of the T6 bear, or Panzer VI, credit to @Ramontxo for photo (smaller) and credit to @BiteNibbleChomp for figuring out the fusion of the Tiger and KV1 with a terrifying 122 or 128 gun, as well as the American counterpart developed, M29, also above. Shows how usage of these heavy tanks on great scale, and terrifying soviet ability to mass produce equipment at extremely rapid pace, will change tank warfare forever, even into the post war, as many cold war tanks were influenced by prominent WWII designs. Tanks might even be MORE heavy post war, however that will change a bit in the modern age, but yet will still have a notable imprint in terms of legacy and frontline tanks.
Then the Mig/Horten 262 seeing ACTUAL mass use and not being a nazi fantasy Wunderwaffe, is going to change factors a bit post war. The shooting star seeing earlier use will probably prompt an even EARLIER global push toward the jet engine, with Japan, Italy, and even China soon trying to cash in on the Jet Engine revolution. War in many ways forces not exactly the speed of technology (at least not as much as popular opinion says) but rather determines its evolution and direction in may ways.