I don’t really distro hop much (you need a rolling release distro and a stable distro, never needed more) but if you’re asking I’ll assume you’re a Linux newb so really I would recommend doing something less custom. If you want Fedora and KDE, install the Fedora ISO that comes with KDE and be done.
I won’t say it’s incredibly complex to run multiple desktop environments, but it’s definitely more of a pain and can cause weird issues (fucking NetworkManager) Better to stick to the “happy path” and make your machine as standard as possible so it’s more compatible with everything, especially if you’re new to Linux