No, you can change your configuration to avoid them.
The warning using interface eth0 instead should be resolved in the future when my patch (see PR above) is submitted and accepted in dnsmasq upstream. As said, the warning is just there to notify you that dnsmasq may be behaving differently than you configured it to. If this different behavior is okay for you, that's okay.
The other warning, reducing DNS packet size can be avoided by
edns-packet-max=1280
as described on the warnings docs page: dnsmasq warnings - Pi-hole documentation
