I assume you do understand that you seeing ads for outdoor headlamp you've ordered weeks ago is a proof that you actually have some privacy? Conversion signal (as in - you've purchased the product) didn't reach the ad network, for whatever reason.

Also - what do you think brings more money for the publisher - ad for outdoor headlamp (that you already bought, but still, you're potentially "lucrative" customer, as you are interested in this product) or a same ad for Windows 10 for 3 years, while you run everything on Linux and never touched Windows in your whole life?

"Tech" is a very very broad category. There's a reason why tech sites serve non-tech ads and personalized ads took over internet.