Nope, regular iOS/macOS on all ends. Literally just stock Apple Messages on devices. I just notice sometimes topics will come up (what appears to me to be randomly) and then relevant ads and/or content will appear on Instagram or web.
I guess it's possible that, to me, it appears "organic" (ex. somebody just mentions Taco Bell or whatever) but they had actually been searching on their device, and since our digital proximities are known, the next thing you know I'm Living Más lol
If you have specific situations where it's reproducible, you can record your DNS and connections on local network and try again. You can only prove/disprove that with enough experiments.