I can still imagine a timeline on which T1 received the 45mm AT gun and PTRS Penals were not a thing, only receiving the sticky satchel.
Trying to balance PTRS as an AT weapon is a nightmare. Cause it's either inconsequential or it achieves critical mass and it becomes stupid and viable.
It's a nice idea but I think giving PTRS Penals more late game scaling (with a second +2x PTRS upgrade at T4) is better because then Soviets have good mobile infantry-based anti-tank. Dealing with Elefant/Jagdtiger + Panzerwerfers/Stukas in team games is so obnoxious because Ziss guns die to the Rocket Artillery and and SU-85's die to the heavy TD's. All Soviets can really do was ram cheese but now that's been heavily nerfed. Whereas both USF and British have much easier times with Bazookas and Piats as well as turreted Tank Destroyers that can flank. Having mobile squads with AT on Soviets gives a lot more potential and opens strategic options. A second PTRS upgrade at T4 allows for late game scaling without being too strong against LV's or Mediums in the mid game.