As to not being able to monitor the performance while recording, this doesn’t seem right. If you click on the Speaker icon located on the vocal channel (bottom on the fader area, to the left) you will find it. Make sure it is greyed out, not orange in color. There used to be a ‘Tape Recorder Style’ recording method option in Cubase but it has gone away. The Speaker icon on the mixer seems the ticket
Trust me, I have a fast machine and I have to run at 256 which leaves me with 5.33ms latency which is enough to kill the vibe - so running Direct is definitely the Way. Good luck.