Assuming "hacker" could be a company what company would have such a motivation and resources to spy on people. The NSO's of the world, sure. Anyone else. Companies have better things to do than spy on people, right. Not anymore.
What about a company whose businesss is personal data mining, who goes so far as to sniff people's residential wifi (they lied about it at first when they got caught), collect audio via a "smart" thermostat (Nest), collect data from an "activity tracker" (FitBit), a "smartphone OS", a search engine, e-mail service, web analytics, etc., etc. Need I go on. I could fill up an entire page with all the different Google acquisitions and ways they are mining people's data.
Why are security keys any different. 9 out of 10 things Google sells or gives away are designed to facilitate data collection, but I guess this is the 1 in 10. "Two-factor authentication" has already been abused by Facebook and Twitter where they were caught using the data for advertising, but I suppose Google is different.
These companies want personal data. With the exception of Apple, they do not stay in business by selling physical products. Collecting data is what they do and they spend enormous amounts of time and effort doing it.
"That's all I know."