It is a doctrinal AT vs light tanks. I suggest you calculate its chance to penetrate a Ostheer PzIV and check its penetration compared to of the 75mm PzIV has.
Then keep in mind that it cost 200 manpower.
Which performs worse then non doctrinal one against these lights, because burst is all that matters if you want to kill armor, unless you get two, in which case you are massively taxed in pop cap and upkeep for inferior unit.
You don't need to be terrified of M-42 so much, no one will be ever getting it unless it'll be able to contest a P4 and to justify popcap and inferiority of a pair of them to single ZiS, it needs to go up against P4.
M-42 even with current buffs is not even worth being a panic button over penal PTRS.