Bad omen stacking raid farm

Stacking raid farm from the era before 1.21, ianxofour's design. Five villagers sit inside composters in pods, the farm hands them bad omen automatically so raids stack back to back with nothing for you to drink, and the raiders funnel into a killing chamber you hold with an autoclicker. At 80000 items an hour it is several times faster than anything built since. It is also dead: 1.21 replaced automatic bad omen with ominous bottles, and the whole trigger this farm rests on went with it. Java, and Paper needs a different build which the creator links separately.

The villager has to be inside the composter, not standing on top of it. That one is the single most common reason the farm does nothing.
Check every villager pod is placed exactly right. One pod a single block too high stops the whole farm, and the raid bar appearing and then vanishing is the symptom.
Difficulty has to be hard, or witches and evokers never spawn and the raid bar stalls.
Never break the armor stand and put a new one down by hand. Doing that breaks the system until you restore the original count in the top dropper.
Keep knockback and fire aspect off the sword and set the autoclicker to about 1.5 seconds. One builder ran two hours that way without a single vex.
Check that the block above the magma and soul sand is a real water source. If it is flowing water the observers never update and no pistons fire.