I specifically looked at Colemak and Tarmak. I didn't like the number of transition steps of Tarmak that reassigns already moved keys.
Ultimately, I came up with my own easier layout[0] and transition steps[1] that's on par with Colemak, or better IMO (on English prose). After much iteration, it ended up looking like an optimized NIRO layout.
One advantage is that it's closer to QWERTY which makes the transition less frustrating. A disadvantage is that the similarity makes it actually harder to easily switch between it and QWERTY until substantial new muscle memory is gained. A funny thing was that on a smaller Surface Go keyboard, I kept QWERTY because my fingers were bumping into each other because of the denser hotspot areas, much like original mechanical typewriters.
One final observation is that I was never a very fast typist and the new layout didn't make me faster. In fact, the amount of typing that I do as a developer in a day wasn't enough to learn a new layout smoothly and had to use typing practice websites to make up the volume. What I do appreciate is that my hands feel much more comfortable all the time now, whereas I was having occasional cramps and on rare occasion shooting pains on the backs of my hands that prevented me from typing for several days at a time.
I have layouts for Mac and Windows. If anyone has an easy to follow how-to reference for Linux (console + X/Wayland?) that would be appreciated. Ultimately an inline USB mapper would be ideal.
[0] https://github.com/qwickly-org/Qwickly
[1] https://github.com/qwickly-org/QwickSteps