offhand:

* Getting 5V8A is likely going to be... a challenge. You might be better off doing 12V3A or so
* Still, getting 40W into your board means either decently challenging power supply on board (probably a DCDC or two), or one or more external supplies
* Yeah, heat is a thing, this is probably getting into aluminum PCB territory if you really want it to sustain most of that power
* You might be better off with off the shelf lighting LED panels and a small control module. Basically separate "lights, cpu, and power supply", and use off the shelf bits
* Is this for fun, or commercial, or a one-off?