Pbkdf2 itself is not the best for the same reasons why sha256 was listed. I do agree that argon2 is better.
argon2 has nothing better to offer. Practically there are 3 argon variants to chose from and they all require careful configuration. It's pretty hard to start with, assuming you can find libraries for it in the first place, last I checked it wasn't commonly supported.
It's a perfect example of theory versus practice. Argon is a researcher's wet dream, ideal by some algorithmic definitions, yet it has no benefits in practice.
Modern GPUs and ASICs can perform millions of SHA operations per second, even with a poorly configured Argon2, you reduce that massively.
If you were to leak your company database with 1 million customers and hashed passwords, there's some theoretical considerations to be made on resistance to GPU and ASIC cracking, practically you're in a pretty bad place whichever algorithm was used. ^^
P.S. Cryptography would have more weight if half the passwords weren't a variation of password2021 and hunter22.
But you can. It’s literally just N times the hash. Typically the number of iterations is chosen to be somewhat slow on the server that derives it. But a specially designed rig can execute this with extreme parallelism and speed.