No specific guides per se aside from Danes balance videos https://www.youtube.com/watch?v=vhc7M2v1UeM&t=493s and watching casts but the general breakdown as I see it
OKW - Crutch on Flak HT and PZ4, I see a lot of Spec Ops, Luftwaffe (mostly to spam Valiant Assault)
Soviet - PPSH Cons, Guards, abusing the currently OP IL-2 strafe, Guard Motor and Guard Rifle Combined are pretty popular. You see some Guards + Snipers builds.
USF - LT builds are probably more popular, Heavy Calvary, Recon, and Rifle are pretty meta you see some Airborne and Infantry too
OST- G43 Grens (Elite, Lightning, Jaeger Infantry) some Mobile Defense for panic Puma. Popular to go heavy T1, skip Tier 2, and rush PZ 4 (build StuGs if you need to against advanced Mediums or Heavies). Pretty dicey to tech to T4 but it's possible if you have lead.
Brits - Lot of people do heavy Infantry section openings with early upgrades and rush a Centaur. AEC if you think you need to counter light vehicle. Vanguard, Special Weap, Mobile Assault are the big 3 - Commando is next I'd say. Emplacements are pretty much dead unless you really need a safe mortar pit somewhere.
Cool, I'll check this all out. Cheers