I use Neo2 [1] on a Moonlander. I find it works really well. Neo2's distinguishing feature is that there are built-in layers that contain special characters, such as those used for programming, control characters, including a numpad, Pos1/End, ... and also many mathematical symbols for significantly faster TeXing.
What makes it such a good fit, in my opinion, is that the modifiers can be placed on the thumb clusters, and even layers 5 and 6 that otherwise require a combination of modifiers can have their own keys. On the other hand, having all control characters already mapped means you needn't find a good location for them anywhere. I still have 5 keys unmapped.
That said, getting used to the Moonlander took almost no effort at all for me, I was back up to speed in a few days.
What makes it such a good fit, in my opinion, is that the modifiers can be placed on the thumb clusters, and even layers 5 and 6 that otherwise require a combination of modifiers can have their own keys. On the other hand, having all control characters already mapped means you needn't find a good location for them anywhere. I still have 5 keys unmapped.
That said, getting used to the Moonlander took almost no effort at all for me, I was back up to speed in a few days.
[1] https://neo-layout.org/