Re: up to 16 systems Free*
Sadly that's some FUD you got going there.
The Free RHEL Developer Subscription allows for 16 Physical or Virtual Systems in any combination.
To quote from the PDF Link to "Individual Developer subscription for RHEL" from their page "https://www.redhat.com/en/blog/new-year-new-red-hat-enterprise-linux-programs-easier-ways-access-rhel#Bookmark%201":
"The Individual Developer Subscription includes entitlements to run any combination of the Red Hat Software included in the Individual Developer Subscription on up to sixteen (16) Physical Nodes or Virtual Nodes for Individual Development Use and/or Individual Production Use."
Cheers Mate.