Maybe it's harder at that size where you have to move your hands, but I use a 3x5 split, and my eyes never leave the screen, so printed keycaps are just pointless.

I use a 3x4. Long press for 'Q and 'Z...

I haven’t had printed symbols on any keyboard, split or not, in many years.

Yes! I did this and love it. My layouts are heavily customized so no standard painted keycaps would do me any good anyway. I use a coherent set of key colors on various layers to provide reminders of what various key clusters are about. Looks great too.

Yes. Was my first ortho and I went full blanks and yeah didn't work out. Went back to normal keycaps to get to grips with it. Now I'm on a Halcyon Elora but still use the Moonlander at home

I don't use symbols on my keyboards. Since they're programmable, the symbols are always wrong.

One thing that might help is setting the backlight colours to mark out different groups of keys.