Comfortably is a euphemism for 'Everyone has to be really great friends with each other'?
I suppose you could go even more radical and add a road wheel. The other option is an unmanned turret with a bustle autoloader and crew partly underneath it.
Look at BMPT. 3 up front. It is not necessary to maintain the hull deck as is. The remote turret module will be new so why tie yourself to the old carousel? Will it be very cheap...no but oth it will probably be quite a bit less than the ground up T14.
Well if they can fit an Armata turret on light afv chassis, they can probably fit it on damn near anything and save a lot of room if they did it on legacy equipment.
In actual fact, that might be a better use of Armata turrets than plonking them on Armata hulls. As least a T72/T90 is a known deal as far as mechanical reliability.
Food for thought that.