I've been speaking to Hikvision about this, they're going to release a fix in the next public firmware release which means you do not have to use the "Hikvision_RTSP" protocol, which doesn't allow you to set motion detection up for the villa and modular intercom main door stations (doorbells) on the NVR .
They estimate this will be available in June.
However, if you need to urgently add your doorbell using the Hikvision protocol, then you can use this customised version:
This is a 'fix' for adding a door station to an M-series NVR. If you do not need this feature, it is strongly recommended that you wait for V5.03 (ETA June 2024).
forum.use-ip.co.uk
Please note that we've found this will factory reset you NVR, so you will need to add all of your cameras and configure all of your settings from scratch.
It did not affect the hard drives for us - we're still able to access all of our recordings prior to installing this customised firmware.
It's also a customised version of an earlier V5 firmware (V5.02.000), so there's a good chance it will have bugs mentioned earlier in this thread.
If you can live without motion detection on your doorbell, we recommend waiting for the public firmware release.