Most mobs use special spawning conditions, which means that these mobs can only appear under certain conditions. If the spawning conditions work, this spam is created in the console.

Spawning Conditions determine which conditions must be met in order to spawn certain mobs. Some mobs only spawn above Y level 60. Some below. Most mobs can only spawn in the overworld than in other dimensions.

It is recommended to play the newest versions of higher minecraft versions.

Not all features of MCreator available or the same in different versions.
For example: Version 1.19.2 doesn't have the feature of shield, better structure generation or custom villagers, but Version 1.20.1 does have them.

You can disable the Boiled One despawning by changing the gamerule "boiledOneDespawn" to true. 
He won't despawn naturall.

You can disable the Broadcast Interferance by changing the gamerule "disableBroadcast" to true. The Broadcast Interferance won't happen if this gamerule is set to false, but the Boiled One can still spawn.

Yes! You can make the Boiled One Syndrom keep you paralyzed like in the actual lore of the Boiled One by changing the gamerule "keepBoiledOneSyndromLocked" to true. The Aggressive version of the Boiled One will still spawn, but only watch the player and despawns if a player without the syndrom is nearby.

You can enable the Boiled One to spawn directly by changing the gamerule "enableBoiledOneSpawn" to true. There is also an Item in creative mode you can use to enable the spawning.

The Boiled One only spawns after the Broadcast Interferance, which can happen during the day in the moon phases 1, 2, 3, 8 or 8, has happend. After that, he can spawn in the overworld or in the nether and always near the player. Sometimes you can hear a trumpet when he spawned.

If you look at the Boiled One, there is a chance that you can get the effect called "Boiled One Syndrom".
This effect can be cleared by using milk or a christian bible and has 3 different stages.

Stage 1: Nothing happens. When you sleep, there is a chance that the Boiled One will spawn nearby and stalks you.
Stage 2: You receive slowness, weakness and mining fatique. Sometimes you hear a quiet trumpet from the boiled one. The Boiled One can also spawn nearby more often but will only stalk you.
Stage 3: You got the Lock In Syndrom and cannot move anylonger. The Boiled One will spawn next to you and will then kill you.