Change to 1.21.8

Changing your Minecraft Client Version

Step 1: Open your launcher and navigate to the Installations tab

Step 2: Click New Installation.

Step 3: Select the version that you would like to play, fill out the details, then click Create.

Step 4: Select the Version List in the bottom left and select 1.21.8 version.

You're now good to go! You can go ahead and press Play and load into the version of Minecraft you had just selected.