Thank you so much, Mark Kelly! My underlying goal in writing about many of these topics is to encourage people to explore new ways to express themselves, and ideally, how to monetize their work. So your kind words really mean a lot to me!
As for Gumroad vs. Substack, I’d suggest Substack (assuming you have the time to invest and are looking for a longer term commitment).
While Medium allows Gumroad embeds, it is sort of antithetical to their ad free model, and this could definitely change over time. Substack was built around the model of monetization I described, and there are few if any potential issues from a platform perspective.
Substack has been one of the simplest platforms to learn, you would be well ahead of the curve in adopting its use, and it opens more doors.
But if you do end up creating a digital product, Gumroad is a fun option to explore!