Here’s my personal thoughts on this… security and privacy are important, and this is an area where Fedora has led before (with SELinux, for example). And looking through the Privacy Guides post, I’m happy to see that we’re doing pretty well in a lot of the areas (and Fedora Workstation and Silverblue are (respectively) their top recommendations for traditional and immutable desktop Linux. I can see the strength in building on this.
On the other hand, increasing security generally comes with a user experience cost. See Should Fedora enforce drive encryption on new installs? for some strong opinions on the downside of default full-disk encryption, for example. Or Network Manager sending regular unencrypted requests? — we could disable that, but then “captive portal” detection wouldn’t work and it’d be hard to get wifi to work at airports and hotels. If we go too far in restrictions, we may push ourselves more into a niche than towards general use.
I’m also unsure we can live up to promises in this area — we generally try, but overall we don’t sharply restrict all of the software we include and in general a lot of it tends to be somewhat … open. I’m not sure how we’d square that with an intentional focus on privacy.
I think we definitely should do some of these things — better Flatpak sandboxing and more secure boot, for example. But I think maybe for the strongest protections we should work with e.g. Qubes downstream, so that people who have the strongest concerns have a good option there — and then we can bring in improvements that make sense.