How did you get your first real users while still in closed testing?

Building Hindigo (an app for people who freeze before starting a task — mostly ADHD-adjacent, but not only) and I'm at the stage where the product works, but it's Android-only and still in closed testing, so I can't just point people at a store link.

For those of you who've been through this stage: how did you get honest feedback and real usage before you had an open, easy-to-share link? Curious about what actually worked vs. what felt productive but didn't move anything — waitlists, DMing people directly, communities, something else?

Also open to hearing if you think closed testing this long is even worth it vs. just shipping rough and iterating in public.