Can a DAC sort out a flat\cold amp?

Thanks for the pic.  It tells everything.  It's your room and the positioning of the equipment therein where the problem lies.  A 1,000,000 dollar amp won't fix that.

The room looks frigid. How to warm up the sound in there with equipment only is a mystery to me. Major reflection effect with that setup. My ears are ringing just seeing it, and not from my tinnitus. The boom box sounding better in the middle of such room makes sense. Work with the room and setup first is my two cents.

The room will be a mess, but I don't think the speakers in that location nor even the reflective surface are going to result in too little bass. I would expect boomy bass from the near corner placement.

Something is broken. One of the speaker polarities wrong, bad amp, etc. Replacing the speaker cables, using Roon (except for equalizer which you can do much cheaper), interconnects, DAC, and a bunch of other things is not going to make any difference. Find out what is broken and fix it.

Buy a microphone and learn how to measure your setup, then you will not need to guess.

+1 Elliotbnewcombjr

A gross lack of bass is NOT characteristic of that amp or any properly functioning modern HiFi SS amp. Other than speakers wired with incorrect polarity (a definite possibility), an impedance mismatch (unlikely) or your seat is smack dab in a null created by room acoustics, I’m hard pressed to come up with another rationale for what you describe. A Schiit Loki may be your best bet if the other proposed solutions don’t provide an answer.