nginx doesn't properly route to webapp and omitting path

I am currently configuring a nginx reverse proxy. The docker instance of nextcloud is available on Port 8891

server {
  listen 8888 ssl http2;
  ...

  location /nextcloud/ {
  proxy_pass http://0.0.0.0:8891/;
 }

}

however when I try to navigateto the url, I have the problem, that the stylesheets etc. are not available under /nextcloud/* instead they are getting fetched from /core/*.

Removing the trailing slash from proxy_pass http://0.0.0.0:8891; navigates me to the docker nextcloud webapp however it's trying to fetch the explicit /nextcloud/ path instead of interpreting it as /

How can I archive, that the sources like server.css is getting fetched from /nextcloud/, and basically the whole nextcloud web app is available under /nextcloud/?

rewrite ^/nextcloud/(.+)$ /$1 break;