Specifically for eduroam, I assume you can be tracked anyways, since you have to authenticate with your personal credentials, right?

1. I usually do the updates in the evening when turning off my laptop. I click "update all" (or so) and then choose "shut down" in the selection that appears at the bottom. Then I can leave the laptop and it will automatically reboot to install the updates and then shut down completely.
2. Yes, that number of updates is normal
3. I don't know of a way to (un)select specific "system"-packages within Discover
4. The updates are usually fine. I can't think of any case where a routine update caused trouble for me. I prefer getting the security updates (and other improvements) quickly. Just once, I intentionally delayed the updates for a few days before an important deadline, where I needed my computer to work and wouldn't have had the time to deal with issues

Why is this downvoted?

You can remove the bar for Firefox: Right click on the toolbar -> "Customize Toolbar..." (or Burger menu -> "More Tools" -> "Customize Toolbar..."), then in the bottom left uncheck "Title Bar" (This works in KDE, at least)

So basically your code is more functional and has larger throughput, while using resources more efficiently? Great, no need for the superfluous copied part!

For public transit routing, I usually use the app of the local provider. But especially (not only) for Germany, Öffi is an open source alternative for them, that uses their APIs, I think.

FairEmail, email app for Android that has every feature I can imagine. Available on FDroid

OsmAnd, mobile app for navigation and maps. Offline, based on OSM, can do anything. I use it for checking out and bookmarking places, finding POIs and pubic transport stations, routing (especially for bike and foot), measuring distances, and so on. It can also show and record tracks, do car navigation, edit OSM points, and more stuff that I don't use. Pro/plus/full version free on FDroid