@mstrshikadance As you've probably surmised by now, the problem isn't the preamps. Its a combination of way too much gain in the power amps and a typical digital source (your DAC) having way too much output.
Your amp reaches full power with less than 1 Volt. Your DAC makes 2 Volts... So you have to knock the signal level down quite a lot.
Normally with speakers as easy to drive as yours, the amp would have less power and certainly less gain. Your cj isn't all that powerful and the power would do OK on that speaker, but IMO/IME cj imbued the amp with too much gain. The gain is useful on less efficient speakers.
So in a nutshell its a mismatch.
The nice thing about speakers that are easy to drive is they tend to also be more dynamic as there is less thermal compression. This makes the presentation more lively and interesting. So if it were me, since all digital products put out 2 Volts single-ended, I would replace the amps with something with less gain and possibly less power. Less gain for sure. Otherwise you'll have to use attenuators and as you already noted, they impose their own sonic 'fingerprint'.