I mean that it looked like either AI generated or blogspam or both. Not the writing though, more the look of the page. Happy to be wrong.

It's neither. Only the thumbnail background is AI generated.

The look of the page -- that's Substack's default UI, you can't control it too much. The other images are created by me.

I'm simply curious what parts give that "cheap" look so I can improve. On Reddit I've had massive amounts of downvotes because they guess the content is AI, when in fact no AI is used in the creation process at all.

One guess I have is the bullet points + bolding combo. Most AIs use a ton of that, and rightly so, because it aids in readability.