I would say that instead of “maintainers” you should be more concerned about the mentors because those are the people that will be volunteering to review your submissions, and there’s plenty of those: https://exercism.io/tracks/elixir/mentors

There are active maintainers, though they have not opted in to be listed on the web site.

There are also active mentors.

So you can safely do exercism. Be aware though, that there is a major PR in review, that will change exercise structure to follow mix project convention rather than beeing loose files.

I am using the elixir track on exercism (albeit infrequently) and all of my submissions have been followed up by a mentor - last one was a couple of weeks ago or so. In fact, my mentor is amazing