iancanada has been designing DIY DAC components for years. Most of his stuff is on the DIY Audio forum and available as group buys. He just posted a video describing "The Best Sound Quality Audiophile DIY DAC I Built in 2020". The components are all original designs and most of them are available for purchase by DIYers. (NB - I have no fiduciary interest in this - but I admire his creativity).
Anyway, he just posted this video describing his "ultimate" DAC system:
Anyway, he just posted this video describing his "ultimate" DAC system: