Doesn't work (can't be loaded)

[VanLoockeMaxim]

When I go to GNOME Tweaks > Extensions and try to enable this extension, I get an error.
I executed the git clone, cd and cp commands as described in the readme (literally copy-pasted them).

Then I did a reboot of the system, and went to Tweaks to try enabling it. When I saw the error, I did the following things (but none of them worked):

• tried turning all extensions off and back on (with the flip switch on the very top)
• tried rebooting again
• removed everything that's from multi-monitors-add-on, and tried the commands again

Here's a screenshot of the error I get. I also included the Ubuntu & GNOME versions, as well as the settings from Multi-Monitors-Add-On (which I can access via the gear next to the exclamation mark)
For easier figuring it out:

• Ubuntu version: 20.04.3 LTS
• GNOME version: 3.36.8