I'm not finding any place where people share their keymap config (if that's the right way to refer to how you've configured which key has which actions bound to it), so here goes mine - and I hope to have feedback and to be inspired by yours, as well!
From some awesome inspiration, I updated the setup :-) thanks!
I moved the layer switcher to the left hand, and moved backspace to my thumb, so I don't strain my pinky so much.

I moved the arrows to right under my right hand... and added a button to make the switch to this gamer layer permanent. So basically, to go from layer 0 to layer 1 permanently, hold left thumb button, tap right thumb button. Tap left thumb button to switch back to layer 0.

And I added a num pad, also right under my right hand, where I'd expect it.

original:
I just got my first mech keyboard with fewer keys than a 'regular' keyboard, and set it up this way:

with the TG(1) switching to layer 2 for gaming/some extra symbols:

and the home row is modded to GASC like in https://precondition.github.io/home-row-mods#how-to-use-home-row-mods with 160ms tapping term.
I am mostly struggling to get used to this way of typing and I still spend a lot of time on finding symbols, or correcting extra or missed keystrokes. But, I'll try to update this when I have more experience.
Critique away!
I use a Lily58 to which I added extra thumb keys, so it's really a Lily60. The layout is intended to minimise using the top row so I could probably move to a board with no num row without changing much. The delay on home-row mods doesn't sit right with me but I use mod-tap to get a few extra keys on the outer column.
RAltis my compose key so that's on a thumb key and all the other alt modifiers areLAlt. There's quite a few mouse controls since I have the first-gen Ploopy nano trackball which has no buttons - e.gMMODEswitches the trackball to scrolling instead of mousing and I often use MB3 to paste the "primary" clipboard. There's a load of stuff I don't use (like the mouse movement keys) but I always try to keep the ASCII layout up-to date in my QMK config:Edit: If code blocks look wonky on your client, here's an image of it
layers