How do I add multiple effects to my custom potion? [duplicate]

To add one more list-style item property to an item, just put a comma , after the first compound dictating the property, and another compound with the next one.

Here is an example with the diamond axe and multiple enchantments:

Enchantments: [
  {id: "minecraft:sharpness", lvl: 255s},
  {id: "minecraft:efficiency", lvl: 255s},
  {id: "minecraft:unbreaking", lvl: 255s}
]

And here is an example with the potion and multiple custom potion effects:

CustomPotionEffects: [
  {Id: 1b, Amplifier: 0b, Duration: 600},
  {Id: 3b, Amplifier: 1b, Duration: 600},
  {Id: 5b, Amplifier: 2b, Duration: 600}
]

Be careful not to put a comma after the last compound in the list!