If you're on Android use the NewPipe app. ReVanced was taken down because in its early stages it had "youtube" in the name of the app so Alphabet sued them. No ads, works just the same.
If you want to Cast to a castable device, TV, or Chromecast, download "Web Video Caster". It works with any website that has media on it. It loads looks at the site, grabs all video or audio media, you select the file from the website, then hit cast. Works for youtube, 123movies, etc.
If you have a smart TV with a store such as a Samsung or LG that locks into only using official apps from their store, you can get the receiver app on the TV's store. Runs on my machine.
There's no reason in 2006+18 you should be watching ads on youtube. If you're on a PC and don't know how to pirate/stream properly- look at my guide:
Go forth and do a fuckin' sping dash.