This is a Datapack for 1.17
The known supported version is 1.17 It may work for other versions, but no guarantees.
It runs these commands during game loading:
doInsomnia false - Phantoms don't spawn.
doMobSpawning true - Makes sure mobs will spawn.
doMobLoot true - Makes sure mobs drop loot.
doImmediateRespawn true - Respawn immediately when you die.
forgiveDeadPlayers true - Makes angered neutral mobs stop being angry when the targeted player dies nearby.
maxEntityCramming 1000000 - Allows 1 million entities to be crammed into a small space.
doTileDrops true - Makes sure blocks drop.
logAdminCommands true - Logs admin commands.
randomTickSpeed 5 - Sets the tick speed to 5.
It also sets the weather to clear every tick.
It runs these commands during game loading:
doInsomnia false - Phantoms don't spawn.
doMobSpawning true - Makes sure mobs will spawn.
doMobLoot true - Makes sure mobs drop loot.
doImmediateRespawn true - Respawn immediately when you die.
forgiveDeadPlayers true - Makes angered neutral mobs stop being angry when the targeted player dies nearby.
maxEntityCramming 1000000 - Allows 1 million entities to be crammed into a small space.
doTileDrops true - Makes sure blocks drop.
logAdminCommands true - Logs admin commands.
randomTickSpeed 5 - Sets the tick speed to 5.
It also sets the weather to clear every tick.
Most of this is adjustable by going into:
data\burber\functions\load.mcfunction (In the datapack)
And for weather:
data\burber\functions\tick.mcfunction
To install:
unzip the file and put its contents in: .minecraft\saves\[WORLD NAME]\datapacks.