The Shell in GNOME 40 has some substantial changes from previous versions. Some of these changes don't work well with the Frippery extensions and aren't easy to address with extensions. It is to be hoped that future updates to the Shell will sort these issues out but in the meantime I've built a custom version with some "improvements".
The custom Shell doesn't start the overview on login. To reinstate the previous behaviour either use dconf-editor or run this command as a normal user:
gsettings set org.gnome.shell overview-on-startup true
It's possible to turn off animations entirely using GNOME Tweaks. The custom Shell adds a more fine-grained option that only disables the up/down workspace switching animation, leaving all other animations unchanged. To reinstate the ugly behaviour run:
gsettings set org.gnome.shell workspace-vertical-animation true
The modified version of the Shell is available here:
The custom Shell and the Frippery extensions live in the frippery-utils repository which can be enabled by installing this RPM: frippery-release-1-2.fc34.noarch.rpm.
(Yes, it says 'fc34' but it works for later versions of Fedora too.)