once you get into ergo (or split ergo), this becomes a LOT more personal – you put symbols where you will find them or where you expect them to be – adjust for whatever layout (QWERTY, Dvorak, Colemak-DH, etc.) you are using and then pile on macros and optimizations to cover whatever programming languages you are working in …

• Designing a Symbol Layer
• 34 keys is all you need
• My 34 key keymap
• You Won’t Believe How Effective This Keyboard Layout Is
• Miryoku

Miryoku is the layout I see referenced most often. Lots of people just do their own, as the other commenter noted.

As others have mentioned, it’s very much personal preference. I program with 34 keys every day with three primary layers: colemak dh, numpad, and nav. After having used Miryoku for almost two years, I’ve been using Callum-style mods for the past several months, and I really, really like it.

I’d recommend taking a look at keymaps in the QMK repo – especially for layouts similar to the board you’re using. You could also search github for zmk-config repos. It’s a different firmware, but layout is layout.