Any tips for getting comfortable with Fedora KDE?

Make backups before experimenting, and try unfamiliar commands or major changes in a virtual machine first. If a command asks for administrator access, take a moment to understand what it will do before running it. That habit saves a lot of avoidable trouble.

Pay attention to where software comes from and how it is packaged. For desktop apps, Flatpak can be a convenient option when it is available. Check the publisher and permissions rather than assuming every package source is equally trustworthy. If you are unsure, ask about a specific app before installing it.

KDE has a lot of useful features tucked away. Virtual desktops can help separate work, browsing, and other tasks. Middle-clicking highlighted text may paste the selection in many Linux setups, too, though keyboard shortcuts are perfectly fine if that already fits your habits.

Don’t feel like you need to customize everything on day one. Use the system normally for a while, then change one setting when you have a reason. KDE’s panel behavior is mostly personal preference, so there’s no need to turn off a floating panel unless you prefer the look or layout.