Finally: by Zero4K and its only (normal) tuner, you can record only from the same transponder or, if you add ad DVB-T USB tuner, of course, from terrestrial.
But one normal tuner allows multiple actions from multiple channels (watching/recording/streaming) only if those channels are on the same transponder.
You, also, are not totally force to use a PVR Kit: you can use and external USB drive or stick. The PVR KIT is only a way to use the second USB embedded in every USB port. It would not be a SATA connection.
The PVR Kit would be useful only not to attach USB hubs to the only Zero4K USB port, which divides the data strream and needs extra power. HUBs are never a perfect solution.