Debian's systemd maintainer today removed both systemd-resolved and systemd-nspawn packages [0] from Testing/Trixie/Debian 13 - soon to be in feature freeze - due to disagreements with the Technical Committee [1].
For operators already using Testing/Trixie/Debian 13 this will lead to dependency version conflicts and/or loss of existing service; for upgrades from Stable/Bookworm/Debian 12 likewise.
systemd-resolved package depends on the exact same version of other systemd packages. When they try to upgrade to newer versions the installed-but-orphaned systemd-resolved package will prevent it unless it is removed.
New installs can use resolvconf.
[0] https://tracker.debian.org/news/1632477/accepted-systemd-2574-4-source-into-unstable/
[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1098914