Cloudmin don’t install DHCP3 Debian 12
Reason being its no longer supported.
Currently ISC-DHCP is the replacement that uses global variables.
But even it is on the chopping block and going to be replaced with KEA-DHCP
Which can be configured for global variables BUT by default it uses subnet based variables and JSON configurations if I recall correct.
May or may not want to beat the curve here it is in the debian documentation.