Both are true. Brute forcing zips is also faster than brute forcing almost anything else. Other formats use key derivation functions like PBKDF2-SHA1 (hundreds of thousands of iterations of sha1) to slow down the calculation of the key from the password, but PKZIP does not do this. Brute forcing zips can be done at 10 billion passwords per second on a typical GPU, whereas rar/7z/keepass are only a few thousand per second.

Here’s an interesting research paper describing both the known plaintext attack and the standard brute force attack https://www.scitepress.org/Papers/2019/73605/73605.pdf