(background disclaimer: native English speaker; can read Japanese and French reasonably well; German somewhat less so; have also lightly studied Latin + Russian + Spanish; Chinese not at all)

Chinese sounds more like the exception than the rule.

I feel like if you're going to say "It just feels like an inefficient language for communication. Why does it have to be so complicated?" you should come for the Indo-European languages first; exoticizing Japanese as this bizarrely complex, weird language just isn't accurate.

In fact, even with the various things you listed, Japanese grammar is still relatively simple compared to most European languages, for instance. No genders, few tenses, only two irregular verbs, a word order system that's both pretty consistent (SOV) and flexible...meanwhile, a lot of what's called "grammar" in Japanese language pedagogy feels more like what European languages would call idiomatic expressions.

Even keigo, which is definitely a pain point...English, for instance, has all sorts of subtle ways of communicating tone and politeness, it's just not quite as explicit. In a way, the strict manner in which it's codified in Japanese makes those nuances somewhat easier to grasp.