We are regularly updating the underlying OS images we use for provisioning.
Some users may want to stick to a known good version and slowly test updates on their own terms.
Internal Staff users are able to provision using a non-default OSV and clients can sort of do something similar using magic user-data comments.
While the magic-user-data comment is documented https://metal.equinix.com/developers/docs/operating-systems/custom-images/ its not very obvious/friendly.
A "proper" input field in the Portal or API and info in metadata would be more discoverable and likely add to its use.
This will also ease the ability for 3rd party OS partners to test their images in almost-production safely, including by their own partners/clients.