The easy way to do this is to hide them with custom CSS - Install Stylebot extension for your browser - make an entry for youtube.com - enter this css: .shortsLockupViewModelHost { display: none} Bam, no more shorts.
To be fair, Ublock Origin is a lot more common, and the less extensions the better, so or a lot of people this would be the better way.
I used to use Stylebot but I switched everything over to Tamper Monkey so all my CSS and non CSS related scripts would be in one place.
Tamper Monkey/Grease Monkey scripts are very portable too, I use my scripts in Safari on iOS via the UserScripts extension.