I didn't play a lot in the Soviet Langreskaya, I played uncountable times in Langres though. I try to replicate how I was played with Wehrmacht by Ostheer. It was like 80%+ win rate
(1) Wire and Wire, like in France
You should well know where is the flanking route, maybe it has some difference. Wire them. Although wiring seems clumsy here and takes a lot of time. Note that, unfinished wire still blocking dudes, use it well. Wire the haystack and other green covers too
(2) MG spamming, but support them well
I find
(3) Teller mines at chokepoint
Yeah, fuck up T70s, period
(4) Pak43, da Wallhaxing bastard
Langres has a lot of shot-blocking stuff, so does Langreskaya. But this wallhaxing bastard ignore those shot-blocking stuff for some reason. Get a Pak43 along with Air Reconnaissance, not even the mighty SU-85 or even ISU-152 can threat your armor easily like in other map. You can even use it base-raping, LOL
Good luck claiming the legendary Soviet Langreskaya for the Fatherland