Languages are not designed, rather they end up being the way they are in a purely arbitrary manner, but basically Chinese Hanzi are hieroglyphics that end up moving forward towards modern times.
Most aren't, but some languages are at least partially designed, like the alphabet (Hangul) of modern Korean (and constructed languages like Esperanto, but those are very niche)
Yeah, but like, Korean as a language wasn't developed, only the syllabaries, and they are still inspired by hanzi, the same way hiragana or katanaka for Japanese.