DHCP-Server: the home router , pihole only serves as the dns-resolver and is announced by the dhcp.
I expect the Client-Window to take every aspect of the client that is known , Name, Mac-Adress, IPv4 and non dynamic Ipv6 addresses to identify the device with all known properties.
Actual Behaviour:
Whenever i add a client, all i see added is the Mac-Adress, the hostname and the description i made.
The only reason to define an individual client in Pi-hole is if you'd wanted to filter that specific client differently than the others, assigning it to a specific group with specific lists.
Your debug logs shows that your clients are attached to Pi-hole's default group only, and there is no other group defined than the default one.
In that situation, there is need to define any clients:
By default, Pi-hole filters all clients via its default group.
You can remove all your client definitions.
As explained by Bucking_Horn, this page should be used when you need to add a client to a specific group, but if you only use the Default Group, there is no need to add clients.
Clients not assigned to any group are automatically added to the Default group.
From DNS point of view, the only information always known is the IP. Only the IP address is guaranteed to be sent in a DNS query.
All other information (MAC address, hostname, etc.) may be present (or not). FTL will try to use other information if available, but there is no guarantee that everything will be returned.
Also, note that the "Known clients" field contains just some of the clients and it shows only suggestions.
You can always type the correct information, even if something is not shown:
