goneinseconds

I have a Nakamich Head Unit with dual RCA inputs, an arena input and a harness input. Do any DCIs work with this? I'd prefer a wired plug and play option.

oth

It should say in your owner's manual whether it is compatible with "steering wheel controls" though it's probably
not as you don't describe an input for that. If not, there is no wired DCI which will work.
It does appear to have an IR remote, so you could use an IR DCI.
Modifry used to make an IR DCI that worked with older Nakamichi headunits, but I doubt that he has tried it on
the newest generation as they are not very common.
PAC used to make a "universal" IR DCI called the "SWI-X" IIRC, but it looks like it's been discontinued.