Now there is a package built for Fedora from openSUSE: Show network:im:signal - openSUSE Build Service
https://software.opensuse.org//download.html?project=network%3Aim%3Asignal&package=signal-desktop
dnf config-manager --add-repo https://download.opensuse.org/repositories/network:im:signal/Fedora_36/network:im:signal.repo
dnf install signal-desktop