That’s the outdated looking website I found that didn’t have mac version. I’m guessing I’m supposed to use the Unix version there?

The website I was sketched out by (but tried it anyway, then got the scary error) was puttygen.com which had me install homebrew (whatever that is) and then do “sudo brew install putty”

"Use PuTTY" is more or less advice just for Windows users.

I think the main reason you couldn't find a mac version to download is that there is none.

The closest I saw was a .tr.gz file (i.e. a gzipped Tape ARchive) of Unix source code, but A) I don't know of their definition of "Unix" includes OS X / MacOS; and B) judging from your comments here, you don't seem like the type who would want to install software by downloading, decompressing, and compiling source code.

I'm thinking the people who told you to use PuTTY were assuming that you are a Windows user.

Homebrew is a reputable package manager (a.k.a. software installer, for Unix applications on the Mac). That said, I'm pretty sure the version of ssh shipping with the Mac could do the key generation for you so you wouldn't need putty.