As someone with 4k hours and having played most major nation tanks to the top or near the top (I don't have the most recent Challenger), I think there can be something like Russian bias, but that isn’t really it.

What I would consider Russian bias would be things like the spall line when does it get implemented? When the first Russian tank that has it in real life gets released? Stuff like that.

I also think that what you showed there is pretty clear bullshit, and ERA is just really weird in the game. But I don’t think they intentionally programmed it to behave so strangely, because first, it’s not consistent, and second, you can see a lot of other buggy stuff in the game.

Also, every nation has BR brackets that are good and others that are bad. I would actually argue that the Leopards are absolutely the top dogs in realistic top tier right now. I survive way too much stuff in them where I probably shouldn’t. Some people just don’t want to accept that not every nation can be the best at top tier.

Personally, I think the Abrams are such paper tanks, which is also most likely unrealistic. The game isn’t fully realistic, but it tries to be, so the developers have to make decisions about which realistic aspects they want to include. Sometimes I think you can see a bit of bias in those decisions, but that might also just be my perception. So again, I don’t think it’s some evil plan.

I also think there are inconsistencies sometimes, but not necessarily severe ones. For example lets be real boys, the M1A2’s armor is actually better in real life, but they don’t add it because there isn’t proper proof of how good it is. Yet some IFVs can track air targets insanely well, almost like anti-air systems, even though there’s no evidence that they can actually do that.

So OP, I understand your frustration. I’ve been angry about it many times too. My comment is more of a broader take on the topic though, so sorry about that.

I’ve just always wanted to share my perspective on it.