[gingertanker]

"Invincible"

No, they are not, neither in real life or in WinSPMBT. They are damned tough beasts though. Yes - if you are trying to kill a Merkava 4 with soviet 1970s or 1980s tech you will have issues. Let me generally comment on capabilities as much as I can while maintaining OPSEC:

1) Protection: A Merkava 4 is incredibly solid at the front. We are talking about stopping Kornets. Like all tanks the sides and rear are significantly less well armored. How much so? I do not know exactly and if I did I would not divulge online to strangers. As for the rear door being a weakpoint, I would not bet on it being any worse than most rear armor on tanks. That clamshell is very think indeed. RPG-7 older models proof more or less...
The active protection system is double and triple combat proven and works very well and if it knocks your ATGMs out of the sky in game, well that's what it does IRL...

2) Sensors - as mentioned the MK.4 took sensors to a new level and future variants will be better. Night time and smoke, other than specific types, are completely irrelevant, we are talking about practically night as day.

Vague but relevant: to a degree the sensory capabilities are under represented in game, and IRL you would see Merkava 3 and 4 units being even faster in hunter-killer mode...I really am sorry for being vague about this but it is simply top secret stuff. Just know that the game actually gives you a bit of a discount on how well Merkava can deal with ATGMs and other major threats.

Now despite all of this Merkavas were and will be knocked out both IRL and in game.

I would propose always preventing your high cost hi tech ATGMs from firing on their own. Hide them and use them only on the flanks of the Merkava. Even better - on the rear. If you let a company of tanks, any tanks, catch a whiff of you as an ATGM based force before you can spring a trap from the flanks - you will suffer IRL and in game.

Let me paint a picture of what happens with OPSEC in mind:

A company of tanks is traveling when they are unwisely engaged by ATGMs from the front at max ranges (let's say 3000m). At this point the APS will protect the front tank. More over it is extremely likely that the front tank will ID the general location or even specific location of the ATGM. The info will be shared nearly instantly via the combat management system. The company will pop smoke and find a position line it can "work" from. Now 11 120mm tanks firing APAM are going to be employed against an ATGM which is a soft target. IRL this includes top attack capability...This is a very bad situation for the ATGMs. They will be suppressed and destroyed eventually. And this is ignoring the tank company will usually have mortar/UAV/helicopter/NLOS support.


HOWEVER:

If Mr. ATGM waits for these 11 tanks to show their sides, and Mr. ATGM and his friends fire at once and use maybe some artillery to supress the tank commanders, the first volley can maybe destroy one or two tanks. At the least it sends the unit into chaos as artillery forces them to button up. The ATGMs should now run the heck away and re position. Their initial positions should be such that allow this to be done out of LOS of their ambushed target. They can re-position and repeat. Even if the tanks are not all killed, doing this will delay their advance because they will look for positions, spread out, than fail to find what to shoot at, so they will again form a formation more friendly to moving forward, and repeat...

Naturally, there are no assurances when the tanks happen to be Merkava 4 with good teams(Or any world class MBT with good teams).