I have worked in the ad industry for 10+ years. Firefox, strict mode but no ad blocker for web. What I would not do though, is using an android or ios phone (or anykind of smartphone where I don't know what the system nor the application do). I am not sure that people realize how many power and data are used on these phones, for things totally unrelated to their personal usage

So you don’t use a smartphone at all? Or am I misunderstanding?

Yes, until recently where I have a Pinephone, but at the end of the day, I do mostly a "phone" usage rather than data/camera/social usages

Why not just use an Android phone with Firefox and the same exact settings that you use on desktop?

I guess it is doable as long as you are doing only that with your phone. If it is linked to a google account for example, the OS and "embedded" google application will still report tons of data that will be then use for advertising

It is a well-known fact they do.

This is why adtech has gotten craftier about ads, and adblockers have had to respond accordingly.

That case is to thwart adblockers abilities to block ads. I think the OP's question was more rhetorical, as in they don't eat their own dog food type of thing.

I’m a web developer, but I use noscript, despite the sites I work on relying on JavaScript and the business not allowing us to make them work without scripting enabled.

When I worked in adtech I absolutely did. I think it was fairly common at the company.