If you have a strong drone force flying around, you will be spotting those targets and taking them out with artillery, air strike or with drones. You don't need a big gun to take them out.
Then your main maneuver force will just move in to mop up and take ground.
Still if some targets somehow survived, they can be taken out with limited number of atgms mounted on the new aa focused tank.
The biggest obstacle to maneuver these days are the drones, not hidden enemy tanks
Most of the targets of direct fire support aren't going to be tanks, it's mostly infantry in built up positions. In an advance, you might not want to wait for other kinds of firepower to show up so you're going to want to have something on hand. Basically, there's always going to be a use for mobile direct fire support. And in the cases where tanks weren't available, the troops on the ground would often use a poorer substitute to fill perform the job. As it turns out, most of the time, even a bad tank is better than no tank.
ATGMs can be used as one these substitutes, but it's often not a great one. I remember reading back in the day how the ATGMs on Strykers just couldn't do the job of the MGS Strykers, and that the latter were needed even though they mostly sucked. Maybe ATGMs are more advanced nowadays, but not all of their problems have gone away.
instead of a "heavy tank" per say would it not make sense to develop a "assault/breakthrough tank" based on the turtle tanks in the Ukraine war?
The name main battle tank is more about role than weight or even firepower or protection. It means that it can effectively perform the role of basically any other tank out there. This tank seems to do everything that main battle tanks are supposed to do. In comparison, the turtle tanks are very limited and I don't think that they are a very good design for other countries to copy.
The point I observed was: The new tank pays too much attention to armor-APFSDS countermeasures.
More appropriate firepower for future tanks is something like 155/30 or 125/40 which pays more attention to the power of HEs and gun-shoot missiles, and It is worth sacrificing the power of APFSDS for this
I suspect that keeping the weight down on this new tank was a very high priority. Being overly heavy will make it that much harder to transport and support. It was a very concious decision to make a lighter tank and this ZTZ-201 should be much more available than a heavier one. Besides, a 105mm HE charge is still going to be very potent. Even though the M10 Booker had a lot of failings, the choice of a 105mm gun was not one of them.