Unable to add anything to Whitelist on pihole docker container

When trying to add anything I get the following notification:

Error, something went wrong! While executing: attempt to write a readonly database Added 0 out of 1 domains

I've checked permissions inside the container. Some stuff online pointed to the problem being that pihole-FTL.db was owned by root. I tried to change permissions, but they automatically revert back to root:root on reboot.

I've recreated the container. I ran pihole -r.

I am at a dead end. Would appreciate any help anyone can give.

In case it helps, my docker-compose:

pihole:
container_name: pihole
image: 'pihole/pihole:latest'
ports:
- '53:53/tcp'
- '53:53/udp'
- '67:67/udp'
- '80:80/tcp'
- '443:443/tcp'
environment:
TZ: America/New_York
WEBPASSWORD: nope
volumes:
- './etc-pihole/:/etc/pihole/'
- './etc-dnsmasq.d/:/etc/dnsmasq.d/'
dns:
- 127.0.0.1
- 1.1.1.1
cap_add:
- NET_ADMIN
restart: unless-stopped