The power supply concerns me a little – the output is rated at a combined 280W RMS and yet it appears that the USB-C module can only handle 45W.
It is 280 W non-clipped peak power, not RMS. You’re only ever going to see very short bursts where the amplifiers are going to output that much. The battery capacity is rated 66 Wh (9000 mAh, before safety buffers that are created in software) and the product should play about 4 hours at maximum volume, which also gives some indication of power consumption.