Refleks shots? Those little buggars are a PITA and can kill on first bite, yes.
Otherwise, I think below a certain criticle range ANY tank gun and Sabot becomes an overkiller at any tank and aspect. I hate to engage at ranges below 2000m. I have not made a statistic on it, but I think I try to manouver that way that most of my firefights are at a distance of 2500-3500m. That gives me a superiority in punch, and maximises their disadvantage in tank guns' punch and precision. At 3000m or so they also do not use Refleks, I would assume. Or only rarely. So: try to fight them at greater range, and try to let the range not become so great that they start switching to Refleks.
Try flanking them. Exchanging greetings with a T-72M4 or T-80 frontally on simply is no good idea. They may not be as strong as your Western tank, but they are still no weak bugs head on.
Do not rely on your supposed better armour. When they start getting hits on you - at this time
at the latest its time to shift position, I would do it, if situation permits, already when their rounds start digging up the dirt in front of me, for it means they have a lock on me. Stay out of sight, or get back into cover. Break their visual.
Simply: Do not get hit.
There is always the chance of that lucky strike, that single round that by chance finds the soft spot in your armour.
Engage with numerical superiority in firepower, where possible. Do not overstretch. Stay in compact formations. I try to avoid thin lines even at the price of allowing gaps in them. I counter that, when possible, by aggressive manouvering, and holding back a tactical reserve as fire brigade. Thin lines is what I rweally hate, and engaging them on a 1:1 basis. It means for every shot of mine they get off a sdhot fo theirs. But having more visuals on one and the same target means that for every shot he lets off, I land two or three or four on him.
At least that is the theory.
Static defence is a monument for the stupidity of man -> Patton, I think. So: stay mobile.