Most DACs have at least a 2V output which exceeds the input sensitivity of most amps.
So unlike a phono input there isn’t a real need for gain in most cases.
There’s many phono stages now that have 60db of gain, so no extra gain needed with them either.
The problem with a passive preamp is some amps don’t have high enough input impedance.
This is true, especially with Class-D, the industry standard was 47k or 50k input impedance for amps, but some Class-D’s are a silly 2kohm!! even 1kohm!!! input impedance, not good with passives and most tube preamps!!!.
You should have 1:10 ratio or more, output to input impedance, to be matched.
EG: If you have a 10k passive it will be at worst position 2.7k output impedance, the lowest amp input impedance "should" be 27kohm or higher, no damage will occur if it’s not, say 1:5 ratio or even 1:1 just cuts the volume down lower and becomes even more of a voltage divider.
Cheers George