Mimi Unbound is a simple Minecraft Bedrock addon that expands your Minecraft world's vertical boundaries, offering extreme height customization while creating a void-based challenge in unexplored territories (chunks) ahead now.
Select version for changelog:
Changelog
Initial Release
Releasin the addon by removing 'Mark as draft'
Actually you can google "Data-Driven Overworld Height and Void Generation Minecraft bedrock" and click the one from Microsoft site.