This is my keymap on a keyboard with a form factor kinda similar to OP's. And this is my keymap on a smaller 30% keyboard.

The 30% Gherkin was my daily driver for several months, I just moved to a split keyboard 3 days ago, that keymap is just a visual aid to help write the QMK code, I use things like autoshift, capsword and combos on the smaller keyboard that are not represented on the images, but it should give a rough idea on how it's setup. I'm not a programmer, I'm a designer for my use case I need to use the modifiers a lot along with symbols and numbers for Adobe Suite shortcuts that's why I make sure to have the mods on every layer.