Boy, I play tanks in all nations on an equal basis (despite being a boat main), Sweden, a bit of Italy and Japan in particular. And I can tell you the Bkan is Bonkers (excellent gun, nonexistent armour). Contrary to what you think I at least have some feel of what minor nations are like.
Used to be Germany, because I tried so hard to make them work and I eventually did. It was also the first nation I got to 5.7-6.7 in. Now I play more top tier planes in sim than tanks and play Germany, USA and USSR more or less equally.
I’ve presented you how developed my tech trees are.
Everyone has a nation that plays the most, that’s completely normal. It’s not like I play only Germany though, which is what I consider as being a main of a given nation.