Because factions are different like you were told 100 times but you fail to understand that. Every faction has weaknesses and strengths.
As I noticed not the Schwere Panzer HQ is your problem but the units surrounding it. In this case like I said you need combined arms. Problems with a pak43? 4/6 USF commanders have offmap arty that can deal with it. Another flak protecting the Schwere panzer? Use a tank after taking the pak43 out. Infantry blob standing around somewhere? Get a scott and wipe the squads.
There is no easy blob tactic to counter combined arms, you need your own combined arms and a witty approach, for every faction.
That's why OKW has weakness in resourscer income, but has cheap tech, powerful units and insane vet 5. No need for ultra bunker a ka schwerer.
Off map arty?
Recon - 120 ammo for one + ammo for recon - no late game.
Mechanized - 8CP, no late-game.
Rifle Company - only decrew.
Armor/Infantry - you cant call it barrage even, waste of muni, no recon to spot.
But the last sentence is amazing.
Volks+Obers+Panther which is the case in 70% of the OKW games + pak43 is called combined arms by you. Are you serious?
Get a Scott, use barrage, get a tanks. It's like your enemy will kindly wait for you.
Get a Scott, owned by Panther.
Get a Jackson, owned by Volks.
Early Sherman is the best way to fight agasint OKW, then a second one and pray to RNG god for wipes.
Once Panther is there, Shermans are useless, Pak43 is covering Panther and most of the time it's gg.
US Forces have so many holes in design that it's amazing they are playable faction.
Versus Ostheer they are deadly.
Versus OKW they are pudding.
That's just incredible bad design.
And like I said before, you are OKW hero, not CoH2 objective player. You have around 50-60 games as USF and hundreds as OKW so how can yoy make objective statement? You can't.