These are all the working duplication glitches in Minecraft 1.21.4 (Java Edition). Each method is fully tested and ...

This design is compact, survival-friendly, and produces a constant flow of iron using the latest villager & golem mechanics.

However, in Java edition, moss blocks can spread to both stone and cobblestone whereas it is restricted to only stone blocks in Bedrock addition. Read: Where are Minecraft Worlds saved on Windows PC?