If you're using Chromium-based browser (Chrome, Edge, etc.), test these with "Allow custom filters requiring trust" checked. Don't use with the rules for Firefox below.

www.youtube.com##+js(trusted-rpnt, noscript, window.Polymer=, '(()=>{let t=document.location.href,e=[],o=!1;const r=Array.prototype.push,n={apply:(t,n,a)=>{a[0]!==window&&"number"==typeof a[0]?.start&&a[0]?.end&&"ssap"===a[0]?.namespace&&(o||0!==a[0]?.start||(o=!0,r.call(e,a[0])),0!==a[0]?.start&&r.call(e,a[0]));return Reflect.apply(t,n,a)}};window.Array.prototype.push=new Proxy(window.Array.prototype.push,n),document.addEventListener("DOMContentLoaded",(function(){let r=!1;const n=()=>{const t=document.querySelector("video");t&&!r&&e.length>0&&(r=!0,t.currentTime=Math.ceil(e.at(-1).start/1e3))};n(),new MutationObserver((()=>{t!==document.location.href?(t=document.location.href,e=[],r=!1,o=!1,n()):n()})).observe(document.body,{childList:!0,subtree:!0})}))})();window.Polymer=')
www.youtube.com##+js(nano-stb, [native code], 17000, 0.001)

Known issue of the rules for Chromium which can't trivially be fixed: occasional failure in blocking SSAP ads.

If you're using Firefox, test these with "Allow custom filters requiring trust" checked. Don't use with the rules for Chromium-based browser above.

||youtube.com/watch?*=$doc,domain=m.youtube.com|music.youtube.com|www.youtube.com,replace=/sabr=1(.+?ssapPrerollEnabled)/\$1/s
||youtube.com/playlist?$doc,domain=m.youtube.com|music.youtube.com|www.youtube.com,replace=/sabr=1(.+?ssapPrerollEnabled)/\$1/s
m.youtube.com,music.youtube.com,www.youtube.com##+js(set, ytcfg.data_.INNERTUBE_CONTEXT.client.visitorData, undefined)
m.youtube.com,music.youtube.com,www.youtube.com##+js(trusted-replace-fetch-response, "useServerDrivenAbr":true, "useServerDrivenAbr":false, /playlist?)

m.youtube.com,music.youtube.com,www.youtube.com##+js(trusted-replace-xhr-response, '/%(?:26|3F)t%3D(\d+)(s?.+enablePerFormatLoudness":(?:tru|fals)e\}),"streamSelection/', 't%3D$1$2,"playbackStartConfig":{"startSeconds":$1,"startPosition":{"streamTimeMillis":"$1000"}},"streamSelection', /player?)
m.youtube.com,music.youtube.com,www.youtube.com##+js(trusted-replace-fetch-response, /(&sourceid=[^&]+&autoplay.+muteOnStart"):true/, $1:false, /player?)

m.youtube.com,music.youtube.com,www.youtube.com##+js(trusted-rpnt, noscript, (function serverContract(), '/*start*/(function(){const e={apply:(e,t,o)=>{if(!window.yt?.config_?.EXPERIMENT_FLAGS?.html5_enable_ssap_entity_id||!o[0]||"X-Goog-Visitor-Id"!==o[0]||!o[1])return Reflect.apply(e,t,o)}};window.XMLHttpRequest.prototype.setRequestHeader=new Proxy(window.XMLHttpRequest.prototype.setRequestHeader,e)})();(function(){const e={apply:(e,t,o)=>{try{if(window.yt?.config_?.EXPERIMENT_FLAGS?.html5_enable_ssap_entity_id&&o&&o[0].includes?.("videoId")){o[0]=o[0].replace("\"context\"","\"params\":\"YAHIAQE%3D\",\"context\"")}}catch(e){}return Reflect.apply(e,t,o)}};window.XMLHttpRequest.prototype.send=new Proxy(window.XMLHttpRequest.prototype.send,e)})();(function(){const e={construct:(e,t,o)=>{if(window.yt?.config_?.EXPERIMENT_FLAGS?.html5_enable_ssap_entity_id){const c=t[0],s=t[1];if("https://www.youtube.com/"!==location.href&&c&&c.includes?.("/youtubei/v1/player?"))try{delete s.headers["X-Goog-Visitor-Id"];if(s&&s.body?.includes("visitorData"))try{t[1].body=t[1].body.replace(/"visitorData":".*?",/,"")}catch(e){}t[1].body=t[1].body.replace("\"context\"","\"params\":\"YAHIAQE%3D\",\"context\"")}catch(e){}}return Reflect.construct(e,t,o)}};window.Request=new Proxy(window.Request,e)})();document.currentScript.textContent=document.currentScript.textContent.replace(/\/\*start\*\/(.*)\/\*end\*\//g,"");/*end*/(function serverContract()', sedCount, 1)

Known issue of the rules for Firefox which we will address: captions will automatically be turned on. There's a workaround but we're seeking for better fix.