My set of recommendations:

RPMFusion is recommended to add to your system. It's the best way to use Steam, certain drivers (nvidia, v4l2loopback, etc.) as needed.

SELinux is present, but the default policy sets are unlikely to impede your usage. The SELinux applet (seapplet) is a useful tool for diagnosing on the very rare chance you're finding permission denied somewhere that cannot otherwise be explained.

If you pull most of your software as flatpaks from Flathub already, your day-to-day experience won't be much different from Debian.

Fedora's equivalent to LTS releases would be the downstream LTS releases provided by Redhat, RockyLinux, AlmaLinux, and others. They don't have the same package sets as base fedora, and may need extra repositories to get some of the less essential, but 'core' software back. Ultimately not much of a reason to run them on a desktop workstation for personal use.

Upgrading is pretty seamless. It's as easy as graphical updates now or otherwise using the system upgrade module in dnf. I generally have the policy of waiting 2-4 weeks for any minor bugs that made it into a new release to settle. I have been expediting my upgrades for the past few releases in order to catch bugs before friends and family upgrade their machines and haven't found any large problems regardless.

Fedora doesn't inherently expect a system to upgrade forever without maintenance, with 5 years being a typical target for things that may break. With that said, it is good to read the release notes before upgrading to the next edition, as there can rarely be something (like the recent recommendation and changed default for a larger /boot partition) that may require maintenance on a long-term system before upgrading. That said, you do have time to hold off on upgrading the distro, as the general lifetime of each release is ~13 months, giving 1 month overlap into a release two releases ahead. For instance, Fedora 43 will still be maintained up to a month into Fedora 45's release.