Probably positions stemming from the Botvinnik variation of the Semi-slav. Conventional chess wisdom doesn't really help, and figuring a way forward is pure cal

Probably positions stemming from the Botvinnik variation of the Semi-slav. Conventional chess wisdom doesn't really help, and figuring a way forward is pure calculation. Then also, maybe lines of the "Irrational system" of the French Defence, Winawer variation (lines of Qg4, and Black sacrificing both g7 and h7 pawns). Playing with nuances about what "complicated" means, perhaps also Nimzowitsch's "Immortal Zugzwang" game, where White is absolutely helpless on an almost full board of pieces.