This amazing skript is available for mc versions 1.16 - 1.19 and possibly 1.20 when it comes out!

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Help:
Commands:
/clearlag on Description: Turns on automatic clears.
/clearlag off Description: Turns off automatic clears.
/clearlag help Description: Shows this screen.
/clearlag clear Description: Starts the countdown for clearing entities.
/clearlag clearnow Description: Clears the entities now.
/clearlag changelog Description: View the changelog for the version you are on.
Other:
Author: 'Charlie6969' on discord.
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Features:
Fully customizable and toggleable countdown timer.
Start clear coundown and clear now.
More to be added soon!