How much proof is there that smart tvs and phones listen to you?

Like, we all know they’re listening , but can we provide proof? My friend was complaining about all the new super surveillance that will be government required in cars after 2027, and I said to him dude you have a stock android, you use every AI slop feature, you use a smart TV on your unsecured network, and uses x every day. They have everything they could possibly need on him. Oh and he posts questionable things to fb daily under his real name.