My Experience 20 hours in
If I didn't know better, I'd assume this game was meant to be some sort of anti-tank propaganda, since it sure as hell seems like that. They seem more expensive targets more than anything and certainly doesn't help that mobility kills (at least in the missions I've played) disproportionately harm a player more than the enemy.
I've looked at the multiple guides here posted on the sub prior, taking things slow and/or finding good defensive positions. I've tried those well enough, problem is there seems to fundamentally be no good defensive position that doesn't also overwhelmingly cripple your sight picture as well. Hull down approaches? Doesn't matter even a T-55 will get you before you can even be warned of it approaching in anything short of an M1P. Full concealment? You're now blind as a bat and even if your commander can see something, you're incapable of bringing the gun to bear because climbing out will expose you and/or leave you at so abysmal a gun angle good luck shooting. And god help you if its an average day in Germany and it's raining. Because none of those problems seem to burden the AI.
The 2 things that have worked, oddly enough are the ones that are as far away from what I assume was intended from a tank sim-lite as possible. Either I fail the mission enough times to memorize where everyone is coming from and then deliberately hug the edges of the map before trundling up from behind as they all suddenly are rendered thunderstruck and incapable of the pinpoint accuracy with little to no warning you have to deal with otherwise, or just use all your fire support systems more than your main gun. Referring back to my first paragraph, if the preferred way to win a fight against tanks is to basically use everything *except* the tank, something has gone wrong.
This isn't even a gunnery issue, on the range I can hit targets quite reliably, the worst it gets is when every so often one tank takes 3 shots to shut down. The problem arises when you're shot at fatally before you can even see the target.
With fragility like this, I'm surprised people still use tanks at all when IFVs are cheaper, and can carry just as much if not more a punch (though admittedly with less magazine depth) with ATGMs, then skedaddle if need be. There's no point to the armored boxes if they die to one easy shot all the less unless you're saved by providence.