What does HackerNews think of CommunityWriterPrograms?
A list of Developer Community Writer Programs
You could try writing blog posts for a company[1]. I haven't done this but I know people who have. It's crazy what some companies pay for such low-quality content sometimes.
Draft.dev
also
To piggy back of what @mooreds said, here's a big list of community writing programs that pay software engineers to write blog posts: https://github.com/malgamves/CommunityWriterPrograms
Depending on your expertise and writing skills, they can pay pretty well.
Here is a repo of options for freelance technical writing:
https://github.com/malgamves/CommunityWriterPrograms
In the process of doing this type of work, you surely will learn new things and probably will help you figure out exactly what you might want to focus on / become an expert at / etc. You'll come to understand systems from a user's perspective which always good for developers.