Is my modem tracking data across devices and accounts?

Genuine question here, I consider myself pretty savvy but I am stumped.

I work from home, and have a company supplied laptop with zero personal accounts logged in through it. I recently started looking after a new client and was researching their business and product using my work laptop, and work email address.

A few hours later I open up my personal iPhone and have a targeted ad for that product on Instagram - it’s quite niche and something I’m …

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