Okay. Point of order
Imagine going to some people
"Okay lads what I want you to do is move off that bit of kit that you know how to use and are trained on and are pretty damn good in if I may say so! Into this thing, yep its apparently American. Treat it as you would your vehicles and fight well! Oh and you've got about 4 days to do so."
You'd be taking men away from vehicles they know how to use and putting them in completely unfamiliar kit, To do so would be utterly absurd. Also those vehicles you mentioned, far far smaller crews than a Grant. So you'd have to break up even more crews and put them into the role, on a vehicle they don't know. And again there's exactly 7 stug's ever deployed to the Africa Korps. Seven. Not 700 or 7,000. Seven. There's a total of 32 (assuming that 5 are not sunk because of course) of these
https://en.wikipedia.org/wiki/Panzerjäger_I in North Africa, no Marders were sent there, they're all in Russia. So you've got a total of (assuming no losses) 39 vehicles which you know how to use, know how to deploy, have the crews for and who know each other and their vehicles and how to fight.
A total of 96 men from the Panzerjager 1's and 28 men from the Stugs, 124 men in total, or the full crews for 17 Grants (assuming you put all 7 crew in)
And you're going to put them in Grants. that they have zero familarty with and this will clearly work because A. Germans. B. Rommel and C. Well it LOOKS like a Stug so clearly its the same.
Its like asking a car mechanic to mend a sports boat's engines or asking a power boat helmsman to drive a 16 wheeled HGV with zero preperation or training.
And again, you don't see the author fiat/hand of the author here? We know how this is going to end, and what you're doing is just set dressing to make it happen.