There have been a couple people testing these sorts of battles.
Various things have been tested such as T-26s against King Tigers, or Panzer 35(t) against IS-3. The general conclusion we are led to from these battles is that equipment really does not matter very much at all in the combat, at least not in comparison to other factors such as morale and experience. It is not that much of an exaggeration to say that morale and experience, along with the quantity of men, pretty much singlehandedly determines battle outcomes.
Below we will examine a battle in which 30,000 unarmed (and I mean literally unarmed, no weapons at all, whatsoever, not even a single rifle or pistols) Soviet militiamen attack a full TOE 1945 Panzer division (with King Tigers).
It probably goes without saying that for such an attack we will need a custom general, namely Yevgeny Prigozhin:

Our leader will have a 0 political rating, 1 morale rating, 1 infantry rating, 0 air rating and 0 naval rating. HOWEVER he also has to have a 99 mech rating, because he can drive to Moscow faster than Guderian. And he needs a 9 initiative rating for daring to be so bold as to drive to Moscow. And he gets a semi-decent admin rating because his logistics had to have been ok to manage to drive on Moscow from Rostov in a day.

Prigozhin's meat wave in this attack were armed with precisely... nothing... nothing at all. All the Soviet rifle squads looked like this. Just 11 guys with 0 "devices" (weapons):

All they had is their bare hands. But with their bare hands alone, they somehow managed to damage 2 King Tigers and 1 Panzer IV. And in addition, other German AFVs were lost in "retreat losses." Technically it was not just their bare hands though. Private Ivanov apparently approached a King Tiger and began gnawing on its tracks with his teeth, which grievously damaged the German AFV. For his bravery in this action, Private Ivanov was awarded the Order of Lenin:

The Germans fired a bit, but not that much, against their unarmed foe:

And here you can see the Soviets fired NOT AT ALL:

0 shots fired, 0 hits of anything against any of the German elements whatsoever.
Notice in the screenshot, however, that it still lists the Soviet weapons (7.62mm Mosin-Nagant rifle) etc. That is because there seems to be some weird bug in the editor where even if you make all the elements have 0 devices, it will still use the original devices in combat (and yes, we tried restarting in case restarting the game would update data and the scenario data was "locked"). We found that the only way to actually make Soviets not fire at all was to not only edit the squads to have 0 weapons, but also to edit the weapons themselves to have 0 of anything. So for all those weapons, I also edited them to have 0 of all stats, to ensure that Soviet militia would not fire at all. For example, here you can see I changed the stats for PPSh-41 to be all 0s. It is the same thing for all the other Soviet weapons.

Here is what the Soviet unit looks like (after the attack):

Notice it has ONLY rifle squads and support squads, nothing else (and the rifle squads are all unarmed, as are the support squads).
Finally, if you look closely at that screenshot, you can find the explanation you have probably been waiting for. The Soviet militia has 99 morale and 99 experience.
Whereas the 1945 full TOE Panzer division was 50 morale and 50 experience (also both sides had 130% ammo, supply, fuel, and support at the start of the battle).
Now, of course, this battle is the extreme case, since the Soviets here are literally unarmed, but are extremely high morale (but it is the extreme case that shows how the mechanics at their core work). However, in other cases that were tested, there were other very strange results.
Here for example is a test by Albert N/Wiedrock in which a 1941 Panzer division with obsolete Czech light tanks does an attack against a Soviet 1945 Mechanized Corps. The German Panzer division was the same as it normally is on turn 1 of a Grand Campaign, whereas the Soviet mechanized Corps was 50 morale/50 experience:

With better Soviet leader:



In either case, the German Czech-tank 1941 Panzer division beats up on the late war Soviet mechanized corps and destroys its T-34/85 and SU-100s etc.
The main conclusion here is that equipment doesn't matter. Yes, it is an overstatement to say it doesn't matter at all. But basically experience and morale and number of men in a battle determine the outcome. You could change the equipment values to more or less anything and get similarish battle results as long as you don't change the morale and experience.
The only way equipment really matters is if the morale/experience differences are a lot smaller between the two sides of a battle (changing that might make the combat engine significantly more realistic), and if the attacker doesn't stack an excessive number of men into the attack (if they do, they basically get a guaranteed win).
Back to the unarmed meat wave attacks, however, for one last final thought. If you repeat the same attack with only 80 morale and 80 experience for the Soviet meat wave rather than 99, you get this:

On the other hand, what if you keep the Soviets at 80 morale and 80 experience, but just increase the number of men they attack with 10x? If so, you get this:

The final test (an in some ways the funniest but most informative) is from Caedus, who tried this same attack (with the 10x more men), but where the Soviets have only 15 morale and 15 experience:

In that case, the Soviets win the battle, but take.... 82k casualties...
There is obviously a massive difference here between how well unarmed Soviets with 15 morale and 15 experience do and how well they do with 99 morale and 99 experience. With the 15 morale, 82k losses. Whereas with my original test, the 99 morale Soviets only lost a few hundred men in their unarmed meat attack.
Now, think about that for a minute or 2... Is it logical that the morale and the experience of UNARMED attackers (or even just poorly armed attackers, perhaps more realistically armed only with rifles and some grenades) should so drastically alter how many casualties they take when (successfully) attacking a 1945 Panzer division with King Tigers?
Sure, there would be some difference because the more experienced troops would be better able to use cover. But I do not think they would realistically take anything like 200x less losses. Instead, the main determinant of how many casualties the Germans manage to inflict ought to be the morale and experience of the Germans. They are the ones doing the firing, and the only ones with weapons in the battle, after all.






