For custom settings during playback and some granular tweaks, the extension enhancer for YouTube might come in handy 👍.
I’ll take a look at DeArrow, looks like a great project thx

I am currently stuck with a super old ipad3 on ios9.3.6 and the only way I have been able to watch youtube on it is through the edge browser, nothing else seems to work. But the version of edge is so old that there aren't any working extensions. I have jailbroken it with phoenix and installed cydia (both of which suddenly stopped working), but it turns out the cydia app that lets you install older versions of stuff has also been discontinued.

I have never not used some sort of adblocker, I am shocked at how often I have to interact with the device to skip ads. You also have to unfullscreen to be able to skip so sometimes I just let the ads run.

I get that ads keep youtube chugging along but, jesus christ, maybe it shouldn't be chugging along any longer. I was trying to watch a 40 minute video yesterday and there were double ads basically every 6 minutes! I feel the freedom to place ads wherever you want in your own video has really destroyed the youtube experience for those who can't or won't use adblockers.

Does this stuff work on mobile?

I use my phone to cast, and/or a google dongle on the TV for Youtube primarily. Almost never from a desktop.... does this work still?

Any idea if there's a way to block shorts using PiHole? I mostly consume YouTube on mobile devices (Android and iOS) but would love to get rid of that garbage.

Recommendation: add Vinegar for all the Apple (iOS, macOS, iPadOS) users. It’s suuuuper good

I love to see all this fantastic innovation but it’s a shame that most of it is confined to desktop/laptop computers. 95% of my YouTube consumption is on my phone, iPad, and Roku. Those platforms just aren’t extensible in the same ways. It’s too bad because I’m least likely to sit at my gaming PC watching videos.

I will mention that if you go premium, ads are removed on all devices.

Also don't forget these two:

• De-mainstream Youtube
• Clickbait remover for Youtube

Ive been yearning for a while a "video or channel for later, go away now. dont show me the same video more than 5 times" plugin

Its ment to cull the garbage and get a more inde youtube, I like an artist called Sui uzi but listen to their diskography once and youtube will drive you to listen to the same tracks repeatedly.

In addition to some of the ones listed in OP, I use

• YouTube Auto Like - automatically likes videos you open them (optionally only when you're subscribed to the channel). If you're on a Chromium browser, Google removed this extension from their web store so you can't install it from there anymore. But you can install it manually if you want by downloading it from the Github repo here.
  
  I also use the following userscripts:

• Return Youtube Dislike - Does the same thing as the Return Youtube Dislike extension in the OP

• Youtube Shorts Redirect - redirects Youtube Shorts to a full watch page, so you can watch them like a regular video.

• Resize YT To Window Size - resizes the video player so that it fills in the entire dimensions of the browser window and moves video players to the top of the page so you can scroll down to see comments, recommend videos, etc.

• YouTube CPU Tamer by AnimationFrame - reduces Youtube's CPU usage during video playback. I don't really understand the technical aspects but it's all explained in the description of the userscript. This script IS NOT compatible with SponsorBlock!
  
  Stuff I'm looking for (if anyone has any recommendations):

• Remove duplicate videos from a playlist

• display playlists in a grid layout instead of a list layout

• block youtube channels i don't like

edit: fixed a formatting mistake

Google does not like this...

I'll gladly take YouTube Shorts Block. It is by far, to me, the most unnecessary thing I've found on YouTube. So when you watch one of these things, note that you cannot control the volume of them. It's always mute or not mute. They also have a tendency to snap in place when you're between videos and in doing so, will restart the video all over again. It is annoying.

I get it's purpose, but I don't need it in my face.

I really like Distraction Free Youtube You can remove the trending tab, shorts, recommendations, comments aka all of the time wasting fluff which really helped me cut back my YouTube usage

Annotations Restored For Youtube is also a really good one, adds back the old styled annotations to old videos that had them, makes old videos a little bit more watchable if they had important info in the annotations

YouTube Unhook is also great

I use YouTube Archivist to download channels I want and view them in Jellyfin. There's now a companion app for FF/Chrome to subscribe or download stuff you're interested in from a browser.