Is the crux of this question that you're trying to increase your attention span?

Others have given good recommendations of long-form content to try, I'd also go as far as encouraging you to see how long you can go without a specific form of short-form content.

For example if you're a daily TikTok user, are you able to go one week without both using TikTok or replacing it with another, similar form of media?

This is a practice I apply to most things I enjoy. Periodically I'll take a break for a designated amount of time and evaluate whether my relationship with this thing is healthy.