Hard to debunk. In the hypothesis it's all bullshit:
What they say is mostly in line with the hard piece of info we have, plus a few educated speculations here and there. The rdr2 thing has been a rumor for a while, so it's worth throwing for added credibility. And the H1 2023 release window could be guesswork based on the guesswork of other people, which was repeated enough to become dogma.
And for the latter, if it doesn't happen during H1, one can always use the get out of jail free card "plans have changed". If the specs are different on some aspects, even better; "plans have changed because specs were modified late. What I said was true at the moment I've said it."
My opinion is that the machine discussed here exists and it's most likely what we'll get as a successor, though things like ram remain up in the air.
I also believe that having not heard of a new Mario, and having Mario Kart content releasing until the end of the year 2023, points to a release of the new machine in 2024 though I can see a scenario where it would release end of 2023.
I also believe that the current Switch will be perfectly fine in 2023 with a new Zelda, Fire Emblem, Pikmin, and long legged games such as Splatoon. And Nintendo knows it.