In general, I group sources into 2 categories, shitty ones and competent ones. I got a noticeable upgrade going from a SteelSeries GameDAC (your run-of-the-mill gamer gadget) to a Topping D10. Like yeah, the soundstage is a bit wider, and the details are more pronounced, and all that. But after that, I couldn't really tell a difference* between well-built, competent sources. So yeah, I had a pretty similar experience to you.

* About that asterisk, one of the things I can notice between different DACs is the effect of different low-pass filters. When I got the Topping D50s, I noticed over time that transients sounded slightly sharper on that DAC than on the D10 or any other DAC that I had. I then looked at the manual and found that the D50s by default used a different filter type than the usual sharp linear-phase filter. So I changed the filter type to sharp linear-phase, and the effect went away.

Recently, I was playing around with the filter types on my FiiO K9 Pro, and I found that if I upsample everything to 96 KHz, the filter type basically didn't matter. If I used exclusive mode on my music player so that 44.1K files were played at native sample rate on the DAC, then the filter type would make a slight difference. This is plausible from a signal analysis point of view, because at high sample rates, the aliases are so far above the audible range that any filter has enough attenuation to eliminate them, but at low sample rates, the slow roll-off filters do not properly filter them out and those aliases can be folded back into the audible range.

Another fun little anecdote: this past weekend I was at a local headphone meet, and I brought along my Stax amp and my electrostats. The store where the meet was held had a DCS Rossini (MSRP $33,000) that I hooked my amp up to. I was able to listen to some of my favorite and most familiar tracks at the meet, and not once did I notice anything new or different about what the Rossini did vs what my K9 Pro did. I respect the engineering and the FPGA-based architecture behind all of the DCS gear, but for me, that tech is more academic than practical. Maybe if I was playing a super-high-res master of the 1812 Overture I might notice a difference, but I'm just enjoying Illenium's new song from his upcoming album.