Not correct. Ostheer is with UKF the faction that is mostly suffering from MP bleed. Their main inf costs 240MP and consists of 4 men that cost 30(!) MP per unit to reinforce. Also every OH unit (besides Osttruppen and Sturmgrens) consists of only 4 men that means they have to retreat after 2 men died on the field.
The G43 is no SMG. Yes it can fire on the move, but you won't insta lose any unit that won't retreat after a second. Besides the G43 is only available in one "good" commander afaik (Lightning War). Rifles with double Bars and Sections with double Brens are way more dangerous especially with vet.
Ostheer mortars indeed are strong but consist of 4 men only and cannot fight Mortar Pits. Allies have units that are way more mobile (besides Brits) and deal more damage up close. So flank the mortar or force it to retreat. If the Ostheer player is forced to keep his mortar in his base all the time, it doesn't serve a purpose there.
Besides a light tank as literally every other faction has 
Also Ostheer has no "dedicated" Tank Hunter (besides the Elefant which I won't mention because you have to stall for it). The StuG is really good but can only take a few shots, has no turret and suffers from bad pathing. Panther is overpriced.
Probably YOU have problems dealing with them. Their strongest unit is the Tiger, which is a very good but vulnerable allrounder. The Elefant is an excellent Tank Destroyer but once circled or damaged, will go down very fast especially against infantry AT. Otherwise there is no OH super tank (Tiger Ace sucks as a cheese tank but you don't see it that often these days and it will get nerfed extremely in FBP). IMO OH is the balanced faction of all at the moment.
so whats your build order against osther as usf
Relic Entertainment
cblanco ★ 
보드카 중대 
VonManteuffel 
Heartless Jäger 
Turkey
