If you want to build this IRL, take cues from the MuteMagic. I wrote a paragraph of suggestions, but then clicked through to the MuteMagic and realized it was 80% of what I imagined. All you need is an IR blaster that can be aimed at a TV receiver; no remote stealing should be necessary for most TVs. Wouldn't be terribly hard to do with Arduino/Raspberry Pi either, if you want a fun weekend project.
As for the advertisement detection... that's the hard part. You'd need a well-tuned solution that doesn't break on scene transitions or channel switching. Definitely an easier project than it sounds though, and I recommend looking into that stuff if it interests you =)
my thinking on not doing the IR blaster remote or dealing with the TV receiver, is the mechanical hand approach could work on non-television options (like a projector where your chromecasting a tv stream)
I probably shouldn't say anything here because they sell out so fast and I need to order a couple still,… but here goes:
There is a fairly new device called an M5stickCPlus2 that you can get around 20 USD.
I know you said you don't have any experience with Arduino but Device has a screen a microphone and an infrared LED and can be programmed with an Arduino, it has everything you need to listen to the TV and mute it.
Good luck
If anyone thinks this is seriously a good idea, I'd be very interested in collaborating. If someone wants to use the idea and not reach out to me, I would be happy to be your customer.
As for the advertisement detection... that's the hard part. You'd need a well-tuned solution that doesn't break on scene transitions or channel switching. Definitely an easier project than it sounds though, and I recommend looking into that stuff if it interests you =)