Which DACs are known to be sweet/rich/relaxed?

R2R and Denafrips....the only way to go....OR I just picked a Shiit DAC for bedroom system and it's fing fantastic.

https://www.mcintoshlabs.com/products/new-products/MCD12000

I am surprised that, for a $12k Dac/CD player, its Dac section does not have I2s input and its player does not have I2s output...

Big learning moment!
To see what the impact of my large, mostly untreated living room is, I decided to drag my 374lbs / 170kg Stella Utopia speakers to my bed room :)

I put a few mattresses and diffusers up against the wall, rug on the floor, thick drapes behind the listening position, etc. Photo here: https://ibb.co/PNCzHnW

This well dampened environment made ALL the difference! Old recordings and playing loud no longer caused any harshness or brightness. Room wasn’t dead either: RT60 was around 400-500ms, about half of my living room.

This reminds me that the room is one of the most important components in the chain.

My 13 x 20ft / 4 x 6m bed room is obviously too small for these huge speakers to spread their wings. But it was a great way to prove a point.

This finding prevents me from chasing different gear. I’ll either install more absorption, or simply accept that a large, mostly untreated living room has its down sides.

Having a custom listening room is next level audiophile. I always thought I had a pretty good system, but until I had a custom room, I didn't realize how far from "good" it was. There is no substitute.

This will probably seem whackadoo but Akiko Audio used to make a product called a Squeezebox. I asked an Akiko dealer about it and he said that he uses one with his solid state tuner because it makes it sound like a tube tuner instead. They're not very expensive but I'm not sure how difficult it would be to find one. However, if you could try one out with your DAC, it might reveal whether or not a tube sounding DAC will make any improvements.