I wish, it re-read the configuration upon SIGHUP, but doesn't.

https://manned.org/man/dnsmasq#head6

DNS & DHCP are generally short lived transactions that are very easy to restart and retry, so as long as it restarts very quickly that seems like a reasonable trade off in implementation complexity to be honest.

That is fair for a home-lab setup.

Oh huh. I was convinced that it did. I stand corrected.