For annoyances that Ublock Origin doesn't block by default, such as non-ad auto-play video:
right-click it, pick the Ublock 'Block Element' to get the URL top-level domain of the server.
Copy and paste that into the 'My filters' tab of Ublock's settings dashboard.
Use the 'My filters' tab to block whatever you want. I kill GIF's (||*.gif , giphy dot com, gfycat dot com), news and promo videos, and anything Facebook/Instagram-related. 70 filters of my own.
Ublock's sub-Reddit has pre-made filters in its Wiki, to block Youtube Shorts; copy and paste them into 'My filters'.