If you want your local domain doesnt forward, you must be change settings,
Edit /etc/dnsmasq.d/01-pihole.conf
Add lines for your local domain(s) as follows;
server=/domain.lan/10.10.10.10
Where “domain.lan” is your internal domain and “10.10.10.10” is your internal DNS server.
Restart PiHole service;
systemctl restart pihole-FTL.service