For uBlock:
! YT Homepage - Hide the Shorts section
youtube.com##[is-shorts]
! YT Menu - Hide the Shorts button
www.youtube.com###guide [title="Shorts"], .ytd-mini-guide-entry-renderer[title="Shorts"]
! YT Search - Hide Shorts
www.youtube.com##ytd-search ytd-video-renderer [overlay-style="SHORTS"]:upward(ytd-video-renderer)
! YT Search and Channels - Hide the Shorts sections
www.youtube.com##ytd-reel-shelf-renderer
! YT Channels - Hide the Shorts tab
www.youtube.com##ytd-browse[page-subtype="channels"] [role="tab"]:nth-of-type(3):has-text(Shorts)
! YT Subscriptions - Hide Shorts - Grid View
www.youtube.com##ytd-browse[page-subtype="subscriptions"] ytd-grid-video-renderer [overlay-style="SHORTS"]:upward(ytd-grid-video-renderer)
! YT Subscriptions - Hide Shorts - List View
www.youtube.com##ytd-browse[page-subtype="subscriptions"] ytd-video-renderer [overlay-style="SHORTS"]:upward(ytd-item-section-renderer)
! YT Sidebar - Hide Shorts
www.youtube.com###related ytd-compact-video-renderer [overlay-style="SHORTS"]:upward(ytd-compact-video-renderer)
Also lemmy.world is extremely slow in pushing out messages to other instances, if at all. So leading the pack is not necessarily the best thing until you figure out scaling.