Here is a helpful talk by a colleague Trevor Larsen who has engaged with the challenges of frontier missions, missiology, movement dynamics, and apostolicity for quite some time, https://youtu.be/32ydw6OSFLw?si=QezfRx9xCUVfKMlt.

He stresses the significance of raising up apostolic leaders and keeping churches connected even as they grow spread and plant new churches. He even engages with how one might understand ekklesia in small and larger ways, the raising up of new leaders to carry on the teaching, growth, and engagement of least reached people groups towards Christ, as well as the challenges and varied personalities of those with apostolic giftings. This video contains both good stories and important missiological reflections for communicating Christ in different contexts and raising up capable leaders to keep movements growing and deepening.