Various binary packages built by this source have a direct Depends on
the dbus package, which conflicts with use of the non-default
dbus-broker package as a system bus.

For details of how to replace this dependency, please see:
https://salsa.debian.org/utopia-team/dbus/-/blob/debian/unstable/debian/replacing-dbus-dependency.txt?ref_type=heads

I don't know whether syncevolution is a D-Bus session bus service or a
D-Bus system bus service. If it's a session bus service (like
dconf-service or MPRIS), then dbus is the wrong dependency anyway:
depending on dbus is not sufficient to guarantee the presence of a
working session bus. The correct dependency for packages that require
the session bus would be:

    default-dbus-session-bus | dbus-session-bus

Or if it's a system bus service (like network-manager or avahi-daemon),
please use

    default-dbus-system-bus | dbus-system-bus

which allows use of any implementation.

    smcv