If you use Ublock you can use this filter to clean Shorts from Youtube (FTR you only need 2 lines near the bottom that have the word ‘short’ in them, but Lemmy formatting is balls so it’s all or nothing):

! https://www.youtube.com
www.youtube.com##.yt-spec-button-shape-next--size-m.yt-spec-button-shape-next--mono.yt-spec-button-shape-next--outline.yt-spec-button-shape-next > yt-touch-feedback-shape > .yt-spec-touch-feedback-shape--touch-response.yt-spec-touch-feedback-shape > .yt-spec-touch-feedback-shape__fill
www.youtube.com##.yt-spec-button-shape-next--size-m.yt-spec-button-shape-next--mono.yt-spec-button-shape-next--outline.yt-spec-button-shape-next > yt-touch-feedback-shape > .yt-spec-touch-feedback-shape--touch-response.yt-spec-touch-feedback-shape > .yt-spec-touch-feedback-shape__stroke
www.youtube.com###sponsor-button
www.youtube.com###top-level-buttons-computed > ytd-button-renderer.ytd-menu-renderer.style-scope > yt-button-shape
www.youtube.com###flexible-item-buttons > .ytd-menu-renderer.style-scope > yt-button-shape
www.youtube.com##.ytd-topbar-logo-renderer.style-scope > .ytd-logo.style-scope
www.youtube.com##+js(set, yt.config_.openPopupConfig.supportedPopups.adBlockMessageViewModel, false)
www.youtube.com##+js(set, Object.prototype.adBlocksFound, 0)
www.youtube.com##+js(set, ytplayer.config.args.raw_player_response.adPlacements, [])
www.youtube.com##+js(set, Object.prototype.hasAllowedInstreamAd, true)
www.youtube.com##.ytp-quality-menu [role="menuitemradio"]:has-text(Premium)
www.youtube.com##ytd-browse[page-subtype="home"] .ytd-thumbnail[href^="/shorts/"]:upward(ytd-rich-grid-row)
www.youtube.com##ytd-browse[page-subtype="subscriptions"] .ytd-thumbnail[href^="/shorts/"]:upward(ytd-rich-grid-row)
www.youtube.com##.ytd-rich-section-renderer.style-scope > .ytd-rich-shelf-renderer.style-scope