Thanks. This is how I ended up setting Bitwarden up for the time being.
However, this guide does not use rootless docker but a normal rootful docker. And while the user account bitwarden is not added to the sudoers group, it is added to the docker group which confers similar powers.
What I am hoping for is info on whether I can get Bitwarden to work in a rootless docker install (where you install docker not as root and without sudo).