FYI, I’ve uploaded the Shell and mutter packages to focal queue it will take some time for the SRU team to review this.
Once it’s ready, if you subscribe one of the bugs, you will be notified to test it to confirm it works (please do it, in bugs #1896332 and #1896334 to make the SRU process faster).
Meanwhile, you can try test packages from this PPA:
It also contains new gnome-shell (and yaru adaptations for that).