Japans 6.3 tech tree lineup is mediocre

So the japanese 6.3 tech tree lineup has one of the worst modifications grinds i have ever encountered. While you get heatfs eventually, volumetric combined with the abysmal reload time makes it frustrating. The vehicles are weirdly both slow and lightly armored. These are easy to deal with by playing more passively, but one thing I struggle to understand is why the gun handles so bad bouncing up and down even when you brake. So many ambushes were messed up because the gun refuses to stop bouncing even when i am at a slow crawl/stopping. I have rarely encountered a tank with such shit handling.

Here we go another “ooh blame volumetric for everything”.
My dude prior to recent BR changes and M44 the 6.3 line was where they finally got good.
ITs not even HEATFS , i primarily use M82 unless its something with heavier armor or open top.
My advice , try treating everything there as an sniper SPG with no armor,don’t engage while moving(unless confident at your aim) and short stopping. See if that playstyle works for you with those.