In my experience moving up in quality DACs provide more than just coloration. Each time I upgraded I experienced a less digital influenced sound, better imaging and clarity of detail. I haven't heard the super high end DACs (Lampizator etc.) but rather than lateral moves I've made significant jumps in price with each upgrade and my next DAC is gonna set me back if I ever get to point that my DAC is the limiting factor.
You can mitigate the diminishing returns by checking out the used market. I just purchased a PSAudio DirectStream DAC that for some reason seems to have fallen out of favor with Audiophiles for close to the same price as the new Benchmarck3HGC. I don't know how it compares with the Benchmark but I can say it's better than my tube rolled MHDT Orchid.
I tend to hear vocal artifacts such as glare or an unnatural sounding tones as a vocalist's dynamics increases which has been vastly improved with the DS. It was also improved with the Orchid compared the Allo Piano 2 with the reclocker where I started..
The DirectStream trade in value is $2000 from PSAudio so I likened it to a used car I used that as my baseline.
For me, my biggest issue now is my streamer. I use a inexpensive fanless PC's USB with its stock switching power supply and WIFI connection. I'm hoping that by decreasing the background noise threshold with a direct connection to the router and a linear power supply . I2S streamers seem to cost more than the DAC so I'm trying alternate solutions hoping to get there without spending the farm. I bummed PI2AES is no longer being manufactured so I'll keep up the search.
Have fun on your search and don't forget to stop and enjoy the music