Move the REPO and WEBROOT vars to the Dockerfile since that's the only place they're needed. Dir is getting created successfully now.

Config/F-DroidRepo/Dockerfile

@@ -8,9 +8,9 @@ FROM debian:trixie-slim
 # Setup #
 
 ARG REPO
-ENV REPO="$REPO"
+ENV REPO="/root/fdroid"
 ARG WEBROOT
-ENV WEBROOT="$WEBROOT"
+ENV WEBROOT="/var/www/html"
 
 USER root
 RUN mkdir -pv "$REPO"
@@ -19,9 +19,9 @@ WORKDIR "$REPO"
 # Install Packages#
 # https://f-droid.org/en/docs/Installing_the_Server_and_Repo_Tools/#debianubuntumintetc
 
-RUN apt-get update && apt-get install sudo bash curl git vim nginx
+RUN apt-get update && apt-get install -y sudo bash curl git vim nginx
 COPY files/debian-backports.sources /etc/apt/sources.list.d/
-RUN apt-get update && apt-get install -t trixie-backports fdroidserver
+RUN apt-get update && apt-get install -y -t trixie-backports fdroidserver
 
 # Generate F-Droid Repo #
 

Config/F-DroidRepo/docker-compose.example.yml

@@ -8,13 +8,13 @@ services:
     build:
       context: ./
       network: host
-      args:
+      #args:
-        WEBROOT: ${WEBROOT}
+      #  WEBROOT: "/var/www/html"
-        REPO: ${REPO}
+      #  REPO: "/root/fdroid"
     restart: always
     environment:
-      - WEBROOT=/var/www/html
+      - WEBROOT="/var/www/html"
-      - REPO=/root/fdroid
+      - REPO="/root/fdroid"
       - FILE0=$FILE0
       - FILE1=$FILE1
       - FILE2=$FILE2

Config/F-DroidRepo/example.env

@@ -11,7 +11,6 @@ MEM=0.25G
 
 ## Repo Settings ##
 
-REPO="/var/www/html/fdroid/repo"
 REPO_NAME="Hyperling's Apps"
 REPO_LINK="https://fdroid.hyperling.com"