The unsatisfied penetration is a good reason to switch to 57mm gun, which has also a better range and much better HE content.
They do have a new mini missile for shooting at targets at reduced ranges and I suspect it will pack a lot of those for dealing with enemy armour at short to medium ranges.
Do you have a name for this mini missile? Is it the one that called Bulat?
There will be Russian tanks and IFVs to deal with enemy tanks, the BMPT is supposed to be dealing with softer threats.
In fact I think the new 57mm medium velocity grenade launcher with a powerful HE round described as being comparable to a 76.2mm shell in terms of HE content could be used for most targets and a light cannon... perhaps a 23 x 115mm calibre weapon might be used against some targets too, while mini ATGMs would be used against enemy IFVs and Ataka or Kornet for enemy tanks.
IMO the roll of the BMPT-3 is not clear yet, the new chassis will give the BMPT-3 better armor, the APS will give better protection, 57mm gun with 23/115 canon and ATGM like Kornet, will give the vehicle a better firepower and give it the power to participate in any battle it choose.
One of his roll could be to defend the flank of tanks or IFV from enemy soldiers and fight in urban area, as the gun will have 60-70 degrees elevation.
BTW India get interesting to buy/manufacture 1,770 Armata vehicle to replace there old T-72.