try building this with updated dependencies

Dockerfile

@@ -15,7 +15,8 @@ WORKDIR /usr/src/paperless/
 COPY requirements.txt ./
 
 # Binary dependencies
-RUN apt-get update \
+RUN echo "deb http://deb.debian.org/debian bullseye main" > /etc/apt/sources.list.d/bullseye.list \
+  && apt-get update \
   && apt-get -y --no-install-recommends install \
   	# Basic dependencies
 		curl \