Apt-cacher-ng & onionized repositories

Hi,
According to the Whonix documentation, this is the correct way to onionize the FastTrack Debian repository:

deb tor+https://fasttrack.debian.net/debian bullseye-fasttrack main contrib non-free

However, how do you onionize this repo while also using apt-cacher-ng?

Currently, I have this:

deb tor+http://HTTPS///fasttrack.debian.net/debian bullseye-fasttrack main contrib non-free

But using that leads to the following error:

SOCKS proxy socks5h://127.0.0.1:9050 could not connect to HTTPS (0.0.0.0:0) due to: Host unreachable (4) [IP: 127.0.0.1 9050]
Reading package lists... Done
E: Failed to fetch tor+http://HTTPS///fasttrack.debian.net/debian/dists/bookworm-fasttrack/InRelease SOCKS proxy socks5h://127.0.0.1:9050 could not connect to HTTPS (0.0.0.0:0) due to: Host unreachable (4) [IP: 127.0.0.1 9050]
E: Some index files failed to download. They have been ignored, or old ones used instead.
zsh: exit 100 sudo apt update

Any idea how to resolve this?