I don’t think you should follow developers, but projects.
If you are interested in back-end development in general, you are in trouble. I can give you a list of about 15 back-end framework in multiple languages off the top of my head, and if you start following all their core contributors, you are facing a list of at least 60 people.
What you should do instead is
At the end, you will have a bunch of people with interesting side projects. It worths noting that many of such side projects will not be related to back-end development, or even web development at all. Taking myself as an example, if you look at my GitHub and GitLab accounts, you won’t find too many web-related repos, but they still might be interesting to you.