https://www.reddit.com/r/uBlockOrigin/wiki/solutions/youtube/#wiki_shorts
! 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 Subscriptions - New Layout - Hide Shorts
www.youtube.com##ytd-browse[page-subtype="subscriptions"] ytd-rich-item-renderer [overlay-style="SHORTS"]:upward(ytd-rich-item-renderer)
! YT Sidebar - Hide Shorts
www.youtube.com###related ytd-compact-video-renderer [overlay-style="SHORTS"]:upward(ytd-compact-video-renderer)
! YT Mobile - Hide the Shorts Menu button
m.youtube.com##.pivot-shorts:upward(ytm-pivot-bar-item-renderer)
! YT Mobile - Hide Shorts sections
m.youtube.com##ytm-reel-shelf-renderer
! YT Mobile - Hide Shorts in search results
m.youtube.com##ytm-search ytm-video-with-context-renderer [data-style="SHORTS"]
Open AdGuard for Safari (MacOS), go to Filters tab, select "User Rules", paste that text above in the textbox, save it and check if if works. (cc @devasheeshG)
edit: grammar