Lago's right, ambush invis is the direct counter to "a lot of range"
OST have doctrinal camo. OKW has JP4. ATGs are safe from M36s, its not that impossible to beat a jackson if they had 70 range.
Except that camo only applies to infantry (and MG42), not the Pak40 or other AT weapons. So yes, you could camo some PGrens w/ schrecks, but that's about all the upgrade would do.
JP4 has 60 range, which means the 70-range M36 would out-range it. You can camo, but that'll only help with your first shot; after that it can still be flanked, or simply out-ranged (back away the M36's speed). Even with two of them, you'd still need an extra shot to take out an M36.
ATGs are safe from M36s, but they also have 60 range; again, you'd need to either push with ATGs (not really going to work), or wait for the M36 to get in range - which it doesn't need to do.
In general, ATGs just aren't viable against super mobile vehicles with a decent amount of HP. They work against LVs since they can usually 2-shot them, but against 480hp+ vehicles, they need 3+ hits to beat them. In that amount of time, the target can easily move out of the ATGs firing cone. ATGs become even less viable when that target can survive 3+ hits, is super mobile, AND has 10+ range over them.