Summary:
The game will be lagged if /effect gives players too many effects at once.
Steps to Reproduce:
Download and import the attached world
Turn on the lever (FYI: This command runs /effect 10000 times)
Observe the state of the game
Expected Results:
The game isn't lagged
Observed Results:
The game is very slow
Notes:
According to the NVIDIA performance overlay, I got 9 FPS, but CPU usage was only 13 to 20%.
My PC specs:
CPU: AMD Ryzen 7 5700X
GPU: NVIDIA GeForce RTX 4060 Ti
RAM: DDR4 16GB
Attachments
Comments 6

I cannot reproduce this using the setup you've provided, as the game doesn't recognize the function "effect". It appears that the accompanying behavior pack is missing.
If this is still an issue, make sure to update the world with a functioning BP or attach it to the ticket.
In addition to the prior comment, it appears that you are intentionally trying to put excess load on the game by doing an action that would not occur in normal gameplay.
Please provide steps to reproduce this in a typical gameplay scenario. (ie, not doing 10000 commands)
In addition to the prior comment, it appears that you are intentionally trying to put excess load on the game by doing an action that would not occur in normal gameplay.
Please provide steps to reproduce this in a typical gameplay scenario. (ie, not doing 10000 commands)