pihole-FTL failed to create listening socket for port 53

sudo grep -v '^#\|^$' -R /etc/dnsmasq.*

?
Might want to edit out some details!

Could try ad below directive in seperate new config file /etc/dnsmasq.d/99-my-settings.conf:

bind-interfaces

pihole-FTL might skip trying to bind to that 127.0.0.2 ip and hopefully start.
Or else you need to configure pihole-FTL to only listen on particular IP's.
And same with stubby ... need to tell it to only listen on 127.0.0.2.

EDIT: