well, first the principle way cubase works with Audio tracks: You can EITHER hear the Signal that Comes from the Input port that is routed to the respective track OR the Signal that has already been recorded to that track. You can never hear both from the same track at a given Point of time.
The decision what you here is selected by the Little brownish Speaker button (Monitor button). When it is pressed you hear the Signal from the Input port, when it is depressed you hear the recorded material.
There are a couple of Options how this button will behave, you find them in the PROGRAM SETTINGS dialogue in the file menu. There is a Manual mode for the button, … plus one mode that is called “tape machine style”. The latter automatically swithces the button ON when you are recording or the Transport has stopped. while “Play” is on without recording, the button will automatically be depressed, i.e. let you hear what you have recorded.
I consider this behaviour what is most often needed.
This leads to the following conerning your question:
Select the “Tape machine style”. And use Punch in recording.
This should work.
In every Situation where you Need to hear the already recorded material while you are recording, a separate track is necessary.