That’s a good call-out, actually. I’ve been specific on those details because I’ve been writing what I know (these guides have all started as notes-to-myself), and all my Pi’s are 4’s with 4GB of RAM.
That said, I’ve received enough messages from folks who are using other models, other OS’s and different overall set-ups, so I’ve amended the guides a bit to sound (hopefully) less prescriptive.
To your second point; I haven’t had any issues with overheating. I only use a fan on a single Pi 4 that runs my Headless Plex Server, and that’s because it’s housed in a heavy case with a third-party power adapter that also powers an SSD drive (to store my music files)