80W is certainly achievable from a fibre-coupled diode laser, but an 80W one runs to many, many thousand of US$ more than a decent CO2 tube costs.
The other choice is a diode linear array - normally water-cooled and run at 808nm, used for medical procedures and in 20W/module, so you gang 4x 20W units to achieve 80W.
I’m interested in knowing who is selling an 80W diode and the format. Care to share?
And just as an FYI, Neje may claim ‘15W optical’, but they’re lying. Any manufacturer claiming more than ~8W optical for a 5V diode is lying. Another FYI is that I look twice at cutting 8mm ply, even on a 100W CO2 - the quality of cut suffers terribly and the speed is very low - 10-15mm/s.
Don’t expect great things in cutting from any diode claiming to be 20W and above.
Anyway, you are looking at the wrong end of the scale when looking for a controller - it’s not just about the bits, it’s also about the speed and the capabilities. If you want a grbl-based or similar board with 3 axes, you either want a LPC1768/LPC1769-based board like a Coherent or a Smoothie, or a DSP controller, like a Ruida or Trocen.
If you don’t want to pay for a Coherent or Smoothie genuine board, there are a few half-decent ones available on Aliexpress like the MKS SGen L : https://www.aliexpress.com/item/33036918120.html
Don’t read that as an endorsement of that board - I was just pointing to one that meets the spec.
It will run Smoothieware and take advantage of the high-speed mode available in Lightburn. It will also run grbl-LPC, Marlin32, and Klipper (although Klipper doesn’t support lasers).