I think my issue was I was building it on a debian 11 bullseye. I managed to get all the individual pieces built and running, there was just one piece missing and I can’t remember which now. I’ll certainly give it a go. Someone just sent me a kvm build of debian sid just for that reason in fact! I believe they are working on the gvm debian package.
I’m on bookworm now myself. Check this out https://forum.greenbone.net/t/external-access-to-gsa-web-interface-ip/1671/4 and thanks I’ll let you know if I run into trouble!