Is there a proper counterbuild if the opponent builds this?

Frozen Heart and other items like it slow attack speed, which makes them stack it up slower. Also, having more raw health makes you still really tanky even with your armor shredded. Other than that, not really, it's an item intended for bruisers so they can actually hurt tanks.

Best counter is to sacrifice tankyness. For damage and other sustain methods. Maybe like healing from LS.

no. there's no counter. i looked. buy warmogs.