I tried building from the source code with
gradlew build
but I got an error
crash-2021-10-24_14.18.42-client.txt
The only thing I changed is Blocks.BEDROCK to Block.OBSIDIAN because I wanted the mod to break obsidian

I was using main branch instead of 1.16.5

Why not just mine it or use withers? Technically this is also good for any block, maybe a config idk if one's gonna ever be added tho.