You dont need IPv6 for your clients to resolve DNS.
Clients are able to query for IPv6 addresses via IPv4 and vice versa:
pi@ph5b:~ $ dig +short @127.0.0.1 google.com a
172.217.168.206
pi@ph5b:~ $ dig +short @127.0.0.1 google.com aaaa
2a00:1450:400e:80c::200e
pi@ph5b:~ $ dig +short @:: google.com a
172.217.168.206
pi@ph5b:~ $ dig +short @:: google.com aaaa
2a00:1450:400e:80c::200e
EDIT: Ow could you copy/paste the text output pls instead of screenshots?
Is easier to read and copy/paste from plus for people searching for similar issues.
With the mouse you can highlight/enclose the text code output with the </> button before posting here so the code gets formatted like above ^