Open Core and navigate to the Library page, then select a module/widget from the list.
Got to the Info page and click on Debug actions, then click Uninstall
Follow through the pop-up that appears and you're done.
Uninstallation
I've put a lot of work into JaxCore, so it's really sad to see you go😓!
If you're experiencing problems with JaxCore, you can search for related issues at FAQs, or create an issue on the Github repository / help thread on the Discord server !
Spoiler
Find Rainmeter in Apps & Features (Windows settings) and click uninstall