So, I happened to set my dnsmasq cahce size to 10000, as a typo. I only just noticed now, however, when I attempt to decrease this to, say 1500, or even 150, I get the error in the title, here is the full detail of the error.
Aug 27 22:58:23 localhost.localdomain systemd[1]: Starting DNS caching server....
░░ Subject: A start job for unit dnsmasq.service has begun execution
░░ Defined-By: systemd
░░ Support: https://lists.freedesktop.org/mailman/listinfo/systemd-devel
░░
░░ A start job for unit dnsmasq.service has begun execution.
░░
░░ The job identifier is 10216.
Aug 27 22:58:24 localhost.localdomain dnsmasq[30448]: dnsmasq: syntax check OK.
Aug 27 22:58:24 localhost.localdomain dnsmasq[30455]: dnsmasq: cannot reduce cache size from default when DNSSEC enabled
Aug 27 22:58:24 localhost.localdomain dnsmasq[30455]: cannot reduce cache size from default when DNSSEC enabled
Aug 27 22:58:24 localhost.localdomain dnsmasq[30455]: FAILED to start up
Aug 27 22:58:24 localhost.localdomain systemd[1]: dnsmasq.service: Main process exited, code=exited, status=1/FAILURE
░░ Subject: Unit process exited
░░ Defined-By: systemd
░░ Support: https://lists.freedesktop.org/mailman/listinfo/systemd-devel
░░
░░ An ExecStart= process belonging to unit dnsmasq.service has exited.
░░
░░ The process' exit code is 'exited' and its exit status is 1.
Aug 27 22:58:24 localhost.localdomain systemd[1]: dnsmasq.service: Failed with result 'exit-code'.
░░ Subject: Unit failed
░░ Defined-By: systemd
░░ Support: https://lists.freedesktop.org/mailman/listinfo/systemd-devel
░░
░░ The unit dnsmasq.service has entered the 'failed' state with result 'exit-code'.
Aug 27 22:58:24 localhost.localdomain systemd[1]: Failed to start DNS caching server..
░░ Subject: A start job for unit dnsmasq.service has failed
░░ Defined-By: systemd
░░ Support: https://lists.freedesktop.org/mailman/listinfo/systemd-devel
░░
░░ A start job for unit dnsmasq.service has finished with a failure.
░░
░░ The job identifier is 10216 and the job result is failed.
I have attempted a clean reinstall, removing all residual conf files, however the error persists.