Very cool work.
As for depth, that’ll be a function of material you’re using. I did an engrave in non pg maple last night that was 0.09” deep in one pass, and I was going 600 speed. I had plenty of room to slow it down and go deeper.
As for beveling with paths — if I understand your intent— in theory if you choose a color scheme you will be able to set power by color, but depending on how smooth you want your bevel to be (how many “steps” of depth you’re aiming for), that’ll be a tedious process.
You could get clever with stacking paths (sort of manually doubling or tripling passes to get greater depth) and reduce the number of colors you’d need, but it’ll still be a bit janky.
I did a bit of experimenting with engraving via path here, it might be of interest:
https://community.glowforge.com/t/super-manual-engraving/15965?source_topic_id=18318