The LXD project had over 300 contributors over the years which while not up to par with insanely large projects like Kubernetes or Linux is still pretty respectable.

So achieving similar level of contributions to a fork would already be pretty nice. It's hard to predict the community reception of the fork though and whether that will lead to more contributions than has been seen in the past when the project was backed by Canonical or if there being two active codebases will result in a reduced set of contributors to both.