The turret doesn't care about APFSDS rounds, which will then stop the main armament from functioning? Enough top armour to stop Javelin despite weighing 35-40% less than equivalent western design which Javelin can defeat? That makes no sense at all.
APFSDS behaves differently from HEAT.
APFSDS does not have explosives, only a rod. When it goes through, the damage is done via hot spalling. So the rod shatters itself and the armour, and damages the insides by setting stuff on fire via intense heat. This can incapacitate or kill the crew, practically vaporise the unlucky ones in the way. But the T-14's crew is in the hull, not the turret. Since the crew is elsewhere, more capable anti-fire systems can prevent fires. On the T-14, the APFSDS round can simply go through the turret without damaging anything. It will only leave behind a hole in the front and the back.
Right now, it's the only tank that uses the principle of six zones:
1. Avoid enemies by using radar to detect them early.
2. Avoid detection using stealth.
3. Avoid target acquisition using EWS.
4. Avoid getting hit by any type of round using APS.
5. Avoid getting killed by using passive armour.
6. Avoid getting the crew killed by placing them in an armoured capsule.
As for top attack ATGMs, it's unclear how much armour is on the top. While the Afghanit and Monolit ERAs can stop ATGMs, even if it penetrates, it's possible that due to the design, where the turret itself is isolated from the tank tracks and engine, even the hull, the crew can simply drive away, have the turret replaced and come back to fight. The internal design should be able to prevent secondary effects.
But the issue with most HEAT rounds is the shorter range of the shell when fired from tanks, while longer ranged ATGMs are more detectable on the T-14's radar, along with personnel getting ready to fire the missile. So personnel and vehicles may not get the opportunity to fire off missiles without NLOS capabilities.
Since the engine, crew, fuel and ammo are separated, the only thing in the turret are the sensors and gun, which are easily replaced in the field.
You can see that there's not much to replace if destroyed.
Long story short, APFSDS goes through the turret without really damaging anything except by luck. And protection from HEAT comes using ERA and radar. The radar can time the automated ERA to explode before the HEAT shell hits it, so this prevents any penetration.
There should be more considering we do not know everything about the tank yet. Particularly the internal turret design and the extent of the APS's capabilities. Let's just say Europe needs a new tank.
There's no T-72/80/90 that can take RPG-28, Kornet or Milan ATGM hits, especially not dozens at once.
Done it plenty of times. Protection against HEAT was achieved back in the 80s, with the induction of composite armour. ERA added an extra layer of protection. T-90s in Syria have taken multiple hits from TOWs and still continued fighting back even with the old Kontakt-5s. Even upgraded T-72s have done it. India's T-72 CIA can do it as well.