There’s no advantage of the A series unless you plan to use the unique virtual GPU features. Nvidia added a toggle for the 4090 to make use of ECC, which apparently the memory can already do, to turn it into a professional card with less VRAM. It’s otherwise nearly identical to the A series cards, minus the NVLINK to connector two A series cards together.
USB-C can deliver up to 240w… that should be enough to power any laptop.