Proud Harbeth p3esr owner - need help tweaking/troubleshooting

Due to the pandemic I catch myself spending more time in my outdoor office space - small 14.5x7.5 feet room with glass windows on two adjacent walls - where the speaker are. It's got wood floors and a 7.5 feet ceiling. The other half has a large desk and a bookshelf. Since it's my private space I have decided to build 'my dream' audio system - different from my main listening room/home theater. I listen to all genres of music from 80's and 90's pop, Folk, Jazz, Electronic, Classic Rock and Latin. No hard Rock or headbangers music.

In my mid-40's and enjoying the audio hobby for decades now, I like my music warm, with non-fatigue listening for hours, where frequency tones are balanced, yet detailed without the grain and glare of vocal peaks or highs, yet presenting instrument separation. I want to enjoy the music. I took the leap, and purchased a pair of Harbeth p3esr. Also, purchased Croft Phone Integrated amplifier to pair with the speakers. Had a Metrum Onyx DAC at home already hooked to my Roon core. Using Morrow Audio MA1 RCA interconnects that were laying around, with Belden speaker wires also on hand. Speakers are on heavy 26 inch stands.

I have around 60 hours on the Croft integrated and Harbeth p3esr so far, but have not found the audio nirvana moment yet. I find the music at times (on certain songs) harsh. It's usually when multiple instruments are played together with sharp pitched vocals. Don't get me wrong - Emma Guzman - Woman the instrument separation and vocals are dreamy, The Game of Love by Daft Punk, the robotic vocals are life like with emotions - but 40 seconds into Wrong Girl by Lindsay Ell and you'll hear her vocals peak and want to run to lower the Croft integrated manual volume knob towards to noon mark (starting point). 

Speaking of which, the Croft Phono Integrated, being a superb hybrid amp, has a lot of gain and is immediate sounding. At 1 o'clock position (noon being the starting point), the sound is comfortable listening at 70db. Turning the volume knob to 2 o'clock it's gets loud to 80db + and 3 o'clock is where you want to turn it down. Never distortion - but enough sweetness and finesse to drive the p3. Loud for the room. 

Metrum DAC has a more or less standard line output level of 2V, and the Croft amp has a relatively sensitive input sensitivity of 250mV. An amp of this sensitivity runs the risk of clipping the voltage waveform before the power stage. Maybe alternative amps have a more relaxed gain structure at the input, sensitive to about a whole Volt. The reason why I am rushing for the volume control as the peas get harsh.

How do I make the famous Harbeth p3esr to sing and show it's true colors of warmth, composure, mature sound, astonishing vocal coming from the diaphragm and the details that it's famous for? How do I listen to hours of different genre music without the need to turn the volume low or move my head up to look at the speakers? Is it the high gain/sensitive Croft Integrated amp or is it the bright Morrow Audio RCA interconnect or maybe the speaker wires? Or maybe the whole set up is a dream and an overkill for the room.

Any feedback by the brilliant minds on this forum with years of experience would be greatly appreciated. With warm regards,