Your phone is not listening to you. https://www.bbc.com/news/technology-49585682
Listening to conversations and turning that into interests that can be advertised against is by far the least efficient method they could use. You can get just as good data through normal tracking.
This is just an example of a frequency illusion where you notice stuff because you're looking for it. https://en.m.wikipedia.org/wiki/Frequency_illusion
I assume it's a different system since it works on Wayland, but idk