Hello,
I have started initial work for structured logging, including JSON and journald.
They include all three (FTL, dnsmasq and webserver) logs and can easily be filtered via the structured journal field COMPONENT=
My current progress can be seen at structured logging: JSON and journald by darkexplosiveqwx · Pull Request #2897 · pi-hole/FTL · GitHub
The current version for journald requires linking against libsystemd, I may be able to provide some instructions on how to try it out in the upcoming days.