Agree with your main sentiment. For accuracy:
> quite a number of languages, such as Chinese and Japanese (and I think Korean too), are written without space between words or characters.
Correct with Japanese and Chinese. Modern Korean (few or no hanzi/chinese characters) does use spaces.
> In fact, until quite recently (last 100 years or so), written Chinese had no punctuations.
Eh… ok, sure, I guess.
Punctuation was formalized in the 20th century, yes.
There are also lexical markers than can be (and often were) used to mark the beginning or end of certain ideas. While not punctuation, these characters serve a similar purpose in delineating linguistic chunks.
The following page gives some simple examples:
https://www.theworldofchinese.com/2021/09/how-china-adopted-...