Wayland is the new standard and X11 is the old standard. NVIDIA support is getting better. The advantages are mainly under the hood, the most relevant for most users is in security and compatibility with newer hardware. If your distro comes with Wayland, use it. If it doesn’t, then don’t worry about it.
Bloat’s subjective and mostly a matter of taste. Unless you’re trying to squeeze every bit of performance out of a 10 year old potato, the bloatiness of your default desktop install will not meaningfully impact your performance. Even the most bloated linux install runs lighter than Windows 10.
Keep up to date, especially security updates. Don’t work in root unless you have to, don’t use sudo if you don’t need it, and configure permissions properly rather than 777ing everything. Be careful adding package repositories: don’t add from other distros or other versions of your distro as that can screw up dependencies. Check your package manager or flatpak before resorting downloading random files and trying to install them manually.
Yes: linux subreddits/communities, Fedora’s own documentation and forums
How easy it is to make a mistake that’s very hard to fix. Also, understanding what “everything is a file,” the filesystem in general, and what a desktop environment even is.