This plugin (tested on Tuinity 1.17, using the Spigot API 1.17) searches for a path from any updated block to the bedrock while in the overworld, causing the block to fall if this fails. As a result, block gravity is simulated.

Requires my small block functions library, QuickBlockLib: https://www.spigotmc.org/resources/quickblocklib.98623/

Simply place the jars in your plugins folder, et voila!

CAUTION: I have only tested this on my own small test server, and while I have taken steps to reduce the CPU and memory impact of the plugin, I do not know yet how well it will scale for larger player counts or different use cases. It may sometimes crash the server, so use at your own risk! And please let me know any issues you encounter so I can try to improve the plugin!

Thank you.