Sorry. Your question is understandable and here it is from the Designers of Shturmovik and Sturmovik FB
1C-Games "Battle over Moscow"
https://il2sturmovik.com/about/#5It is a hardcore-battlesim, part 2 of
"Battle over Stalingrad" sommer, autumn und winter 1942 to the end of the 6th german army january 1943
"Battle over Moscow" autumn and winter 1941/42,
and "Battle over Kuban" spring/sommer 1943
Every of them can be used as a Stand-alone-Product, but to see the complete story it is not a bad idea to have them all. It is not a must for the typical simmer, but for all virtual pilots that want to fly over the Eastern Front of WWII it is simply the reference, because there is no other option. One point must be sad and I am a fan of good documentation, but this lacked completely. There is Forum in English, German and Russian that do its best to give the information needed and reaction time is about 2 hours but the Fans can not always do the job of the designers. I have written this in my review about "Battle of Kuban" for the german speaking FS-Magazin (Flight Simulator-Magazin) and this Article is in the Plus-Form online after the next Paper-Magazin is out. If you want I write with permission of the Editor-in-chief of the FS-Magazin, Mr. Groner, a summary for you all here under Reviews if you have not enough from my bad english...
It has an option for online-fighting also, but I have no use for it, because I didn´t want to fly with this guys, that misunderstood historical correct simulation with just "another shooting game."
I flow first in the "Battle over Kuban" and step by step I have bought the other parts. I still want to buy some of the collector aircraft, The Lavochkin La-5FN, Messerschmitt Bf 109G-6, Yakovlev Yak 1b... the rest is in my inventory. I am not always happy. some of the german aircraft have the tendency to break out on take off, like the original, typical for the Bf 109, the fixing of the tailwheel failed and it resulted in a crash with the beautiful german nickname "Ringelpiez". With my Thrustmaster" T.1600 and no pedals I cant stemm against this...
Today the italian Macchi M.C. 202 "Folgore" came into my inventory, the finest aircraft of italian design in WWII, that has been flown in small numbers in to combat also on the eastern front over Moscow and maybe (must look) Stalingrad.