ravencode.
Some context btw; I had pihole & DHCP working fine but needed to upgrade to bookworm which caused problems, so did a full OS reinstall with some data retrieved like DHCP config, home directory and pihole teleporter backup
1) possibly, I copy pasted my old dnsmasq file I had before.
2) yes, I've always had to config my DNS manually per device or setup a DHCP server since my ISP router doesn't support changing DNS apparently.
3) I followed the pihole alternative 1 method here, also restored via teleporter:
https://docs.pi-hole.net/main/basic-install