I also tried 8.1 ISO many times. Both versions did not work for me. But know I am just interested to know how Proxmox would partition my single disk to try to do the same (or almost) manually.As a data point, there seem to be several people having problems with the Proxmox 8.2 ISO installer... but when they go back to the Proxmox 8.1 ISO installer things work ok.
Not sure if that's useful information now though, as you've taken a different path for installing things...