Using the multichannel analog inputs on your Yamaha RX-Z1 does NOT bypass the volume control. So if it cannot be set to a suitable volume without problems, then you cannot use it as it is without problems.
What is the problem with the volume control?
In that case, you can probably use it, as you would adjust the volume on it once, and leave it alone, and for normal changes in the volume control, you would use your new preamp.
However, I think I would just go with a new receiver instead. It would be easier and take up less space, and you could get rid of the old receiver.
Among the ones you listed, I would go with the Yamaha RX-A3030. But it really depends on exactly what you want from the receiver, as well as your budget.
I would be more likely to go with the discontinued Yamaha RX-A3020:
There isn't anything I would particularly want in the new one that is not in the old one. But, again, it really depends on what you want in a receiver.
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