The script just needed to integrate or to type before running in Catalina Terminal: sudo mount -uw /
However keep in mind that the "CMD+R" associated to your machine is only the latest macOS installed or re-installed or beta updated.
For example, if on internal disk I have two APFS containers with Mojave and Catalina, and I install/update Catalina, then "CMD+R" Recovery is Catalina, if instead I re-install or update Mojave to its next beta then APFS Recovery becomes the Mojave one.
I tried that and this happened. I wasn't asked for my password and upon reboot with CMD+R, nothing. The computer froze and needed to be hard reboot.
So then Continuity Activation tool, I get this warning when I run it...
And this when I reboot into my admin account. I normally use a standard user account, like I am now.
Nowhere in my settings do I have a check box to enable Handoff as I did in previous OS's