The point of the QWERTY layout was to prevent jamming; the prototype layout was roughly alphabetical on the keyboard and jammed constantly, so it was refined to fix that mechanical problem.
The part that is a myth was that they prevented jamming by “slowing typists down”. What they did is moved commonly adjacently pressed letters apart from each-other so they wouldn’t be pressed at about the same time. This was not done explicitly to speed or slow typists (at the time, there was no established typing technique and there were no expert typists), except insofar as a constantly jammed keyboard was extremely slow.
But the nearness that mattered was in the ring of typebars on the Sholes/Glidden/Schwalbach/Densmore typewriter, not the nearness of the keys on the keyboard per se. This typewriter connected the keys to typebars which were placed around a ring and struck upward at the platen. The association between keys on the keyboard and the positions around the ring is not obvious.
https://blog.nms.ac.uk/app/uploads/2018/08/Figure-13.jpg
https://blog.nms.ac.uk/2018/08/11/re-typing-history-the-shol...
They started by trying to place common English digraphs onto typebars at opposite ends of the ring, then swapped keys around via trial/error until they got the jamming problem mostly under control. Later the Remington company did a few more swaps so that "TYPEWRITER" could be typed entirely on the top row, as a marketing gimmick.
See https://en.wikipedia.org/wiki/Sholes_and_Glidden_typewriter#...
The true part of the common QWERTY criticism is that the layout of the keys was not decided primarily based on the positions on the keyboard or human hand anatomy. As a result, the keyboard layout per se (both the positioning of the physical keys themselves and the choice of association between letters and keys) is not especially efficient or ergonomic.
A related (milder) criticism can be leveled at the Dvorak layout, which was designed for the typewriter technology of ~1930, where the home row and top row of the keyboard were easy to press but the bottom row was much slower and less convenient, based on the consistent steep step between rows of keys. Computer keyboards have always had a different physical shape compared to 1930s typewriters, so the relative difficulty of typing different key combinations is different, and an optimized layout therefore looks different.
