ok, one issue was that configuration was not stored. Updated the command line. This means the same vault will open if you restart/recreate the container.
docker run -d \
-v D:/ob/vaults:/vaults \
-v D:/ob/config:/config/.config/obsidian \
-p 8080:8080 \
--name obsidian-remote \
ghcr.io/sytone/obsidian-remote:latest