For learning system administration, I think Cent OS Stream can be a great choice. Not because it offers something special than others but because it would familiarize you with the RHEL/Fedora family and in my experience majority of enterprise-servers are using one of its family members, be it RHEL, the former CentOS, Oracle Linux, Amazon Linux or some other variant.
Because it is specifically tailored for hobbyist users who would want to build their OS bottom up, stack-by-stack. In Arch world, they claim they strive for simplicity and that simplicity is achieved through forcing you to familiarize with every part of your system so that it is simple and easy for you to pin-point the root when an issue occurs. They put a lot of effort in writing a great documentation that the Arch wiki. Usually the BBS community don’t expect you to know everything but want to see that you did your own part before seeking community help. Please don’t read it as an excuse for the cockiness of some community members but plenty of times the users are at the fault. Answer to many questions on BBS are simply direct citations from the wiki. There is nothing wrong if someone is not willing to read that much just to get an OS working, but then they should just acknowledge that they don’t fall into the targeted user-base and stick to something else that suits their need better.
Despite all of its privacy concerns, one can’t really get rid of it if everyone around is using it as the default communication mode, unless you’re a social outcast. The thing with communication apps is that they aren’t a personal choice.
My path is similar to yours except went from Ubuntu to Arch. Haven’t felt the need to look for other distro since I moved to Fedora (GNOME)
With First Party Isolation is place, containers now add up very little to your privacy to be honest. They are mostly helpful in convenient compartmentalization of your browsing activities without actually having two different browsers.
Firefox is already very privacy focused, and its default settings are pretty good.
Partially incorrect. There is unnecessary telemetry that you would prefer to get rid of, for an example there is a setting for extensions recommendation as you browse. Also, probably because of their deal with Google, Firefox defaults to Google’s location services even though Mozilla has its own. You may want to change that as well for better privacy. I am only citing a handful few examples, there is more for you to dig in. uBO is a must have with right set of filters enabled according to your own privacy threat vectors. There is a reason hardening is a common practice among Firefox users.
For an example, Mozilla being forced to use Google Location Services as default even though Mozilla has its own. I am also a Firefox user but it always makes me wonder what other TnCs forced on Mozilla as part of the search deal.