How can I enable transient /etc?

[ivant]

I have spent a lot of time trying and it seems like I'm just doing something wrong.

I am building a container like this:

FROM quay.io/fedora/fedora-bootc:41

# ...

COPY <<EOF /usr/lib/ostree/prepare-root.conf
[composefs]
enabled = true

[etc]
transient = true
EOF

and nothing happens, any changes that I make to /etc after installing that image through kickstart remain.