+1 for what you say, but - being pedantic - I think you will find that an ortholinear is one of the grid type layouts (like the Planck). I actually made exactly the same error in terminology on another forum, so there is no shame in it. ![]()
I have started another thread specifically to agitate for the Atreus as an option. This I consider the most practical option for the 13.5" Framework since it allows for the retention of the trackpad (on which any thumb clusters / arcs might impinge) whilst still being a relatively popular configuration.
Larger or deeper models offered in the future may have sufficient space for thumb-cluster keyboards and trackpad, or allow a pointing stick instead of trackpad which can fit between any thumb clusters.
I agree that ease of customising layouts is really important to me, and vital for smaller alternative configurations like the Atreus that really need layers. There is a thread specifically on QMK (and other configuration software) here.