I bought a used LampizatOr Golden Gate 1 for about 6 K and sent it in for upgrade to GG3 status including a new VC/OLED display and JL Sounds USB upgrades. That will get you in the 10K range. The GG uses DHT's in the output and also has a tube rectifier. It replaced a Denafrips Terminator Plus. The DHT's are amazing. I am using it with an Allnic L-8000 DHT pre-amp. The Lampi is dead silent in spite of the DHT's.
The upgrade was phenomenal in terms of timbre and tone with fine resolution. It is the sweet spot in the line up. However, I found the S/PDIF better than the USB, not that the USB is not great, but you are back to that.
FWIW, I use an Antipodes S20/S60 DDC to convert USB to S/PDIF, its an improvement over a Denafrips Iris. I share your observations about USB input. I also use a Sonore Optical Module and Sonore Signature Rendu to take advantage of the Ethernet output of my Innuos Statement which in my opinion is much cleaner than the USB output. I'm not saying USB can't be done right, just in my system the Ethernet output and S/PDIF input are superior to USB.