Enderman wither rose farm

A wither rose farm built on the End island, designed by Rays Works and built here by Shulkercraft. A wither is spawned into a sealed box made of enchanting tables, which it cannot blow up, and a chicken sits in a chamber where the wither can see it. The wither fires at the chicken and everything caught in the blast takes the wither effect, so the endermen packed into the drop shaft above die and each one leaves a wither rose. A named endermite pulls the endermen in, carpets stop them teleporting away, and hoppers run the roses down to eight chests. The end gateway next to it has to be broken first, which is what the bone meal, dirt and red mushroom are for.

The list is missing one cobblestone wall. mist6493's comment saying so has 649 likes, and you can craft one out of end stone up there if you forget.
Take Thorns armour off before the wither spawn at 7:54. Thorns damages the wither, the wither retargets you, and the farm goes with it.
From about 1.21 onward, raise the enchanting table in the drop shaft by one extra hopper so the endermen stand higher and cannot reach the wither. fahlur needed two blocks on 1.21.11 because of the reach change.
Swap the enchanting table in the chicken chamber for a stonecutter. It is a smaller block, so the wither can actually see the chicken and locks onto it instead of the walls.
Waterproof the End island around your portal before you spawn the wither. Otherwise it targets endermen outside the box and blows the walls out, which is MadelineGaming's fix.
Bring far more ender pearls and bone meal than the list says. bjowa needed 70 pearls before an endermite appeared and JonGiha used nearly a stack of bone meal on the mushroom.