Iron golem slime farm

The old school slime farm, built inside an actual slime chunk. The video covers finding one two ways, off your seed with a chunk finder or by digging with a beacon if you are on a server, then the build itself: flat spawning platforms stacked under the chunk, six iron golems penned in the middle to pull the slimes across, magma blocks to kill them and hopper minecarts underneath to collect. It is from 2020 and it still works, but two things about it are out of date. The torch pattern predates the 1.18 light rules, and 1.18 also made the caves under you enormous, which is what quietly kills most builds of this farm.

Since 1.18 slimes spawn at light level 7 or lower, so torching the platform the way the video does costs you most of your rate. Glow lichen or redstone torches keep it bright enough to block other mobs and dark enough for slimes.
Light up every cave near the farm. Nearly every dead farm in the comments is unlit caves eating the mob cap, and there is far more cave to light since 1.18.
The iron golems are much harder to pen in than the video makes it look. Place the back fences first, spawn the golem, push it in while standing on the fences, then close the last block.
AFK about 120 to 126 blocks above the top layer rather than the 24 blocks the video uses.
Building it under an ocean removes the cave problem entirely, and you can carry the platforms up to y 40 because slimes spawn that high.
Widen the hopper minecart collection to 5 blocks. Slime gets stuck on the edges of the narrower one.