There was a guy who was trying to sell DCC decoders to 3 railers in the early 2000s. I am talking 2001-2002. He had small ads in OGR and CTT. The decoders were available and worked well. I saw his display at York several times. I don’t recall if he only had decoders for engines that had can motors or not but they did exist at least for Can motored locomotives. Unfortunately, they didn’t have sound and TMCC already had a stronghold in the market so after a few York’s he stopped showing up. He kept his website up for many years but even that is gone now. There just isn’t a market for DCC in 3 rail.
My opinion on control systems is there there are pros and cons to each system but what is the most important thing to me is when I send a command to a locomotive that the locomotive responds immediately and every time. I get that with DCC. Sure there are some really cool things that the 3 rail systems do that DCS doesn’t but what’s most important to me is getting the commands reliably to the locomotive.