Unlike many Western counterparts, the BTR-4 Bucephalus is fully amphibious in its standard configuration, the Ukrainian MoD states. The vehicle is equipped with two waterjet propulsors at the rear, enabling speeds of up to 10 km/h in water.

The transition to amphibious mode described as “rapid” – requiring checks that hatches are sealed and fitting the air intake snorkels.

What really differentiates russian and Ukrainian design lineage armored vehicles is an emphasis on practical organic amphibious capability. If you compare the armor of these vehicles to most "western" armor the comparisons aren't favorable until you include the context of extremely good amphibious capability.

There is a reason most russians ride on top of their equivalent wheeled and tracked APCs, the armor is a deathtrap pressure cooker waiting to be detonated by a drone or ATGM.

Somewhat counterintuitively though for a land army advancing over a vast terrain in the end the ability to cross wetlands and rivers in unpredictable places is almost as useful as having thicker armor. Or that was how the theory is supposed to go.

Not sure the armor is thick enough on these designs, but I imagine the slat armor upgrades address that so long as they don't overload the engine and negate the amphibious capability.