Correct, the three models currently on sale are all Mariko units.
Bloomberg reported for a while that a Switch capable of 4K graphics (and DLSS) was in the works, and in June 2021 said the announcement was imminent. Additionally, we knew from a Nvidia leaker of a chip known as Dane that would fit the bill (and IIRC they suggested themselves it was for Nintendo). A month later we got the OLED Model announcement with no graphical improvement to speak of, still on Mariko.
However, some insiders claimed this device was still coming, and evidence for a new chip built for Nintendo continued to mount through a Nvidia data breach (I'm not referring to it as a leak as it was the result of an illegal cyberattack). Some details were unsurprising, such as an architecture that would have Tensor cores, supporting the DLSS info. Other info was surprising, such as the name - it was Drake, not Dane. There's theories as to whether Dane was a planned chip that actually existed at some point or whether it was just a mix-up the entire time. It doesn't really matter; Drake's details corroborated what insiders heard, and is likely the only chip we ever truly got wind of.
And now we're here. Notably, John doesn't go as far as to claim when or what device exactly was cancelled, just that a mid-gen refresh was planned "at one point" and now is not. Many have interpreted this to mean the OLED Model was supposed to have some sort of spec bump (I personally think there's some holes in this idea, but there's holes in every theory right now) at one point, Nintendo ultimately decided they didn't need one, and the Drake stuff we've been hearing about has been the next-gen hardware the entire time and is thus unrelated by this cancellation. However, in response, Nate revealed he's been hearing for a few months that the exact device he's heard about for 2023 is no longer coming to market, though he isn't ruling out the possibility Nintendo uses Drake in some other sort of device (draw whatever conclusion you want from that) that likely comes sometime later. Many are struggling to reconcile a timeline where a 2023 refresh got canned this late in the game if there's also a successor just a year-ish down the road from that anyway (as the two projects existing at the same time and using the same chip would be a rather strange scenario), and are thus dismissing Nate's info as bunk.
I'm in a wait and see mode myself. At present, I'm not expecting significant hardware in 2023.
There's some tomfoolery in the Nvidia data breach suggesting Dane maybe possibly was something, but no one really knows.