I can confirm the procedure. Worked on all 8 different no-subscription test nodes without issue.
I just followed procedure on the wiki, but below is what i did:
1. apt-get update
2. apt-get dist-upgrade
3. comment out sources.list.d/pve-enterprise repo entry
4. add non-subscription repo entry in sources.list
5. apt-get update
6. reboot
7. logged on WebGUI.