/gamemode @s creative
/op @PlayTheColorfulCreature
/op @Xanderjedi11
/give @s lever
/give @s command_block_repeating
places it down
/fill ~ ~ ~ ~499 ~499 ~499 tnt
(Inside the command block)
places another command block
/execute as @e[type=tnt] at @s run summon tnt ~ ~ ~
(In the command block)
/give @s redstone_dust
(Places it down connecting the two the putting the lever at the end)
(Pulls lever)