Have you tried watching movie recaps on youtube? It's the other extreme but i find it good enough for movies I'll never see. There's lots of movies I've seen there I'm glad I didn't watch for a full hour. Most movies have tons of similar tropes you can easily understand in like a 15 min sentence
Jellyfin is adding a new MediaSegments API/plugin, which should allow any arbitrary segment of any piece of media to be skipped on (eventually) all Jellyfin clients.
Probably too small of an audience but I'm amazed that someone hasn't released a podcast app that has sponsorblock. Podcast ads are so predictable I'd imagine an ML model would have no issue detecting them.
The problem from what I've read is most ads are inserted on demand in the stream when you first play/download a podcast and there's no easy way for software to tell them apart, not to mention they're usually location based which means the ads you get are likely different from what I get, and depending where you live you might not even get ads at all.
I use antenna pod which is able to download as well, which seems to suggest that at some point the ads get fixed. Also they're very consistent for me, enough that I can usually cut off the first 30 seconds of ads for certain podcasts (there's a function to skip predefined sections).
Or even if it was only reported manually via humans, it would still be worth it to give them the option, and on more popular podcasts it could help lots of people. In the meantime, I just listen to the YouTube video version of the podcasts, which usually have sponsorblock.
For YouTube content I really like the Tubular app on Android. It has Sponsorblock built-in, which you mentioned, but it also has an option to skip silence.
I find it particularly nice for gaming content, or any point where the YouTuber is reading text aloud.
I must have skipped hundreds of hours of pointless silence by this point