Proper way to request backport of patch from (future) systemd-248?

[Kevin P. Fleming]

I recently tracked down a bug in systemd-networkd and supplied a patch
upstream to fix it.

PR: https://github.com/systemd/systemd/pull/18494
Issue: https://github.com/systemd/systemd/issues/18378

I'm currently doing the dpkg-source/patch/dpkg-buildpackage dance on
the machine where I had this problem so that I can continue using the
Debian systemd packages.

I had hoped to stop doing this once systemd 248 was released and made
its way into Bullseye, but with the soft freeze in place and no
planned date for the release of systemd 248, that seems unlikely.

What's the proper way to request that this patch be backported into
Debian's systemd 247?