I know a lot of people like the LTSC version but just a warning, they are slightly different then the regular home and professional versions in terms of policy settings.
This can make it more difficult to use things such as https://github.com/HotCakeX/Harden-Windows-Security
If you are someone interested in trying to harden your windows device but are not familiar enough to change all these policy settings yourself.
Not necessarily, there are tons of things that are very secure but not at all private.
But… having a massive attack surface and known security issues and thinking your data is somehow private because you use a FOSS application is silly.
EDIT to answer your edit: partly. I mean regular timely security updates seems to be a struggle for most of these android OS but also because it provides a bunch of privacy by default options that these other android ROMs don’t such as a private relay, default RCS messaging, and makes them easy for users.