Click the following link and install the Request Blocker Extension
https://addons.mozilla.org/en-US/firefox/addon/request-blocker-we/
Click on the Extension button in firefox and then click Manage extensions
Click on three dots on the right side of Request blocker extension and then click options
Paste the following text in the Request Blocker Options field
://.rumble.com/embedJS//?request=related
Then click save button
Congratulation!!! You have successfully disabled the Rumble Autoplay in Firefox. Good luck with your courses without any deviations.