Optimize subdomain registration in DNS.

Hi, I have been searching for 2 days how to make custom records in Pihole using domain/subdomain.

I have not found any solution.
The Pihole configuration is very basic, isn't it?
IP domain
subdomain.domain IP

Wouldn't it be better to have the custom.list file something like:

subdomain IP
subdomain2 IP

Some records I have to register 2 times, one to access the web and another time to access by ssh typing less. Example

printer IP (write only printer by ssh to access the printer server)
printer.domain.com IP (to access CUPS)

If I register only the whole domain (subdomain.domain), when accessing by ssh I have to write the whole thing, it is not enough the subdomain because pihole does not find it.
I think it would be something very easy to implement and would save us many lines of configuration and DNS registration.

It's unclear whether you are using Pi-hole as DHCP server or not, which may already address your issue in certain constellations.

Note that
a) domain and domain.subdomain are indeed two different domains from a DNS perspective
b) custom definitions follow the HOSTS file format, i.e. IP <list-of-hostnames>
c) certain software may expand a name resolution by a search suffix while others won't

You may want to explore dnsmasq's expand-hosts option (see also Clients unable to resolve Pi-Hole hostname - #9 by Bucking_Horn).
It's certainly worth a try, but be aware that using this option may conflict with Pi-hole's own use of it when Pi-hole's DHCP server is enabled.