New or Old CD Player?

Wow - searching for the proverbial "white whale" of a high dollar, one box redbook CD solution - now you are a hard core audiophile imgoodwithtools!  In my experience, I have not been overwhelmed with the most recent "advances" in digital, and with a few exceptions, and there is no question that the quality of redbook cd drives has been declining over the years.  Thus, I think you may be better off with some of the more recent CD players that have experienced significant price depreciation; the best of these I have heard in your price range are the EMM Labs CDSA-SE, the Esoteric X-01 (or if you are lucky you can find a K-01 in the ballpark of your price range), and the DCS Puccini.  I would definitely prefer these over the CD8 from my limited experience, but have no context to comment on the Simaudio.

Your own short list and Rzado’s offerings all rank as high-end performers. You can add , inter alia, the top NAIM and older top-end LINN spinner and also the REGA ISIS Valve cdp/DAC into the mix .

they are all very fine units .... they are all contenders and no pretenders in that price and performance strata. Which sounds best in YOUR system is impossible for others to suggest,

The REGA (and others?) has a USB direct input into their high end DAC to permit digital playback of hi-Rez audio files on hard drives ...a nice feature IMO for a change-up .

The REGA has a nice feature: two other exclusive matched serial numbered bespoke transports reserved for its buyers in the remote case of replacement .... a nice piece of insurance going forward.

happy hunting

Get an old one. Oppo was making some decent disc spinners but they are getting out of that business. It might be a sign of things to come. If it were me, I would look for an older Sony ES model, Esoteric, or even a PS Audio. You might find a new old stock unit from Sony like the 5400ES. That might be a great idea and run out the digital cable to a really good DAC, like the Ayre Codex.