Drained monument guardian farm

dudieboy's guardian farm, the one that does need the monument drained. You tear the monument down, drain it with sponges and rebuild the spawning area as a glass and prismarine tank, so the farm ends up looking like part of the ocean rather than a box. Guardians spawn in the tank, get pushed down a drop chute and die on campfires at the bottom, and hoppers feed the storage. The base build is around 15,000 items an hour, and the last section of the video shows how to use pack spawning to roughly double that. Java only, and the draining is most of the work.

The roof over the spawning area has to be a solid block. Helldevil6893 found guardian spawns fail about 95 percent of the time when the roof lets sky access through, so no glass up there.
Break the sponges with a hoe. An Efficiency IV hoe insta mines them, which the creator only learned from the comments himself.
calebbeard6130 places all that sand with an observer, a piston and 3 redstone, then just holds right click.
poughkeepsieblue makes the drop chute tall enough that the guardians die on impact, so the campfires become optional, and puts water buckets in dispensers to catch them for XP instead.
mobamba4282 was stuck at 18,000 an hour until he found it was his collection system choking, not the farm.
It is Java only. The spawning does not work the same on Bedrock.