Custom installation of docker nextcloud - docker-compose

Question

I'm trying to configure my nextcloud on my digitalocean server (debian 11). Using nginx proxy manager and nextcloud under docker
I change the root directory of the docker-compose (since I was out of disk space, I added a volume and mounted it at /var/lib/docker/volumes/volume_nyc1_01)
I created a new folder called nextcloud. Inside that created docker-co
Version: "3"
volumes:
nextcloud-data:
nextcloud-db:
npm-data:
npm-ssl:
npm-db:
networks:
frontend:
# add this if the network is already existing!
# external: true
backend:
services:
nextcloud-app:
image: nextcloud
restart: always
volumes:
- nextcloud-data:/var/lib/docker/volumes/volume_nyc1_01/var/www/html
environment:
- MYSQL_PASSWORD=raspberrypi
- MYSQL_DATABASE=nextcloud
- MYSQL_USER=nextcloud
- MYSQL_HOST=nextcloud-db
networks:
- frontend
- backend
nextcloud-db:
image: mariadb
restart: always
command: --transaction-isolation=READ-COMMITTED --binlog-format=ROW
volumes:
- nextcloud-db:/var/lib/docker/volumes/volume_nyc1_01/var/lib/mysql
environment:
- MYSQL_ROOT_PASSWORD=raspberrypi
- MYSQL_PASSWORD=raspberrypi
- MYSQL_DATABASE=nextcloud
- MYSQL_USER=nextcloud
networks:
- backend
npm-app:
image: jc21/nginx-proxy-manager:latest
restart: always
ports:
- "80:80"
- "81:81"
- "443:443"
environment:
- DB_MYSQL_HOST=npm-db
- DB_MYSQL_PORT=3306
- DB_MYSQL_USER=npm
- DB_MYSQL_PASSWORD=raspberrypi
- DB_MYSQL_NAME=npm
volumes:
- npm-data:/var/lib/docker/volumes/volume_nyc1_01/data
- npm-ssl:/var/lib/docker/volumes/volume_nyc1_01/etc/letsencrypt
networks:
- frontend
- backend
npm-db:
image: jc21/mariadb-aria:latest
restart: always
environment:
- MYSQL_ROOT_PASSWORD=raspberrypi
- MYSQL_DATABASE=npm
- MYSQL_USER=npm
- MYSQL_PASSWORD=raspberrypi
volumes:
- npm-db:/var/lib/docker/volumes/volume_nyc1_01/var/lib/mysql
networks:
- backend
As you could notice, I created through mkdir, each folder after volume_nyc1_01.
Finally I started the server, from /var/lib/docker/volumes/volume_nyc1_01/nextcloud, using docker-compose up -d
Once logged in the ip-addres-server:81, I created the proxy host with domain name mydomain.com and forward hostname/ip nextcloud-app port 80. Saved
When i check in the domain name, it just doesn't show anything. The same happens when tried to establish the ssl.
I know I'm missing something, but I searched a lot and couldn't find anything. I really appreciate any help or suggestion