I think too much weight is put on the term pre-amp mode
Yes, I can only agree with you.
A DAC chip is always optimized to convert the digital signal to its full extent = 0 dB.
The so-called "preamplifier mode" in most DACs is nothing other than part of the DSP function of the DAC IC used, with which the volume is digitally reduced before the D/A conversion. There are no additional components for this on the analogue side.
Without additional and effective safety measures on the part of the manufacturer or the user, it is like driving in the back seat of a car with a loaded and cocked weapon. You all know that scene in Pulp Fiction? The pothole will not announce itself.
Exceptions to this are DACs like those from RME with their own volume control in front of the DAC chip, or devices like those from Benchmark that have an analog volume control.