Perhaps, more correct...

Dockerfile

@@ -3,7 +3,7 @@ ARG MONGO_VERSION=latest
 ARG PORT=9001
 
 ## mongo build stage
-FROM mongo:${MONGO_VERSION} AS database
+FROM mongo:$MONGO_VERSION AS database
 WORKDIR /
 COPY mongo-init.js ./docker-entrypoint-initdb.d/
 
@@ -20,10 +20,10 @@ RUN yarn build
 
 ## this is stage two , where the app actually runs
 FROM node:20-alpine AS containerize
-ENV NODE_ENV ${ENV}
+ENV NODE_ENV $ENV
 WORKDIR /home/node/app
 COPY package*.json ./
 RUN yarn install --frozen-lockfile --production
 COPY --from=build /home/node/app/dist .
-EXPOSE ${PORT}
+EXPOSE $PORT
 CMD ["node","server/index.js"]

docker-compose.staging-build.yml

@@ -9,7 +9,7 @@ services:
             context: .
             target: database
             args:
-              - MONGO_VERSION
+              MONGO_VERSION: 4.4
         networks:
             - docknet
         volumes: