For context Germany (Merz) isnt a 2 Party-System. (sic)
Sure, that's true. Angela Merkel's approval rating, however, reached as high as 77%.
Imo this 5% barrier and ignoring 20% of votes is a problem.
I am also not a fan of the 5% threshold. If, as opinion polls now suggest could be a real possibility, the AfD manages to gain an absolute majority with less than 50% of the vote in Saxony-Anhalt, it will be more than a problem but a full-fledged constitutional crisis.