Can a DAC sort out a flat\cold amp?

First of all I would not pump any more money into this set-up.-which is being used as a work station and a defacto hi-fi set up

Your aim is to improve the sound of what you have at minimal cost.

I would replace speaker cable and inter connects though.

I would also lose the table , display and keyboard , electric fire , flip flops and any other clutter. Use headless control via mobile phone.

Get the speakers away from the walls.

The PC it looks ancient and may have a limited speed cpu ? - Replace HD with  SSD if not already done.

A clean Install of windows server 2019 - Free trial available Reduce number of services running in back ground.

Remove as much clutter on SSD and install HQPlayer -free for 30 days. Employ highest HQP settings that the cpu will permit.

Pull CPU out and replace with quality  thermal paste 

Install ROON +HQPlayer

Ethernet connect from router to pc -disable wi-fi

@bobby1945 

All great ideas Bobby.  OP should implement all.

This post just goes to show what a mess you can get into down the digital rabbit hole.  The faults being heard are almost certainly due to digital issues and like most here I would exonerate the amp.  But adding a digital equaliser won't solve the problem.  It's sending a spider to catch a fly.  Just adds to the mess.

Like Bobby says clean up the whole system and simplify.  Where possible put individual components in other systems to verify they operate correctly.

That amp could easily be sold here or on ebay. It is or was a popular Amp. Maybe it would do better paired with a warmer speaker. You may just have a synergy issue. You could also try a tubed dac such as the Border Patrol r2r dac. It may warm it up a bit. Cabling can also be used to tailor the sound. If Possible, leave that Amp on continously for a week. Maybe it will burn in more.

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.