There is no evidence of risk. A general freakout is not evidence of anything besides maybe some bad acid.
First of all, please don't try to pretend that claims that the data remains encrypted and secure and only in trusted environments are claims that should carry any weight. The data cannot only exist in encrypted form. The entire goal of these systems is to mangle and aggregate the data "enough", then share that result as plaintext with the highest bidder.
> I mean, everything you do on the computer is also in RAM - is that tracking too?
No, not everything I do on my computer is tracking. Most software doesn't keep a long-term record of detailed interaction data. I don't expect my window manager to log how much time each app spends in the foreground. But even for the stuff that is logged, you should be able to understand that the real concern comes from when that information is exfiltrated from my computer, processed by a third-party, and sold.
Your "no evidence of risk" is my "no evidence of a lack of risk", and at the end of the day, I don't see any reason to blindly trust any company on their claims of being benevolent, let anyone one operating in such a historically sketchy one like adtech.
Uh... what do you mean? It's not like every programs has free access to the RAM and can just whatever that's in it, there are boundaries. Just because something exists in RAM doesn't mean it can be read, collected and analysed by someone else.
Also, data existing in "encrypted form" and being executed in a "trusted execution environment" mean nothing either. People whose goal is to collect the data can still decrypt it and read it, and a "trusted execution environment" basically means nothing if they whatever they get by analysing that data in that "trusted execution environment" is going to be disseminated to third parties who may or may not have the capability to use that data to identify you.
It's not nice to accuse people of freaking out over "maybe some bad acid". Even if it's "freaking out", in this case it's actually safer to "freak out" and avoid it than taking your ill-reasoned advice.