Sites where you can put up your own content with author name.

My goal is to start making myself an expert in my niche. I want to eventually be on higher authority websites with an author box and my name.
What sites can you do this on and does anyone have advice on being able to be an author on bigger sites?
Medium.com I guess would be a start? Any others?

Substack is an alternative to Medium.

The route I'm taking is writing books through Draft2Digital (not affiliated), which then get distributed on several influential platforms. At a later date I can then use these books as a portfolio, when requesting to write for various websites.