There are a lot of things between "modern Russian tank" and "completely unprotected humans". The 30mm gun is excellent against armored personal carriers.

For the tanks, the A-10 carries the AGM-65 Maverick with 136 kg (300 lb) of explosives.

Upgrading the gun would be useful. We can now make even the 12.7 mm ammunition have guidance, so 30 mm should be easy. We could compensate for the density reduction by upgrading to something like the 37 mm used by the MiG-17. Guidance would allow targeting the most vulnerable parts of a tank. The toughest modern tank still relies on vulnerable sensors. One could also just pound the same spot many times, chipping out a hole. Reactive armor is nothing if you can get a second shot in the same location.