When I want to restart my run, my world is saving for long time, what I must do for fix that? Example:

use fast reset mod

wait nevermind, fast reset isnt available in 1.17

You could probably decrease the full screen resolution or turn down your render distance down to 2, so the game doesn't generate as many chunks.

you could have two instances of Minecraft open

when you reset you save and quit then switch to the other instance and repeat

you don’t need a macro or anything

set render distance to 2, set graphics to fast, turn particles to minimal, turn off clouds

things like that make the game lag less