Good temp, but how about the dev fees? And where's the firmware?

If the dev fees are 3%, just the same as new firmware lurking around, then that's too high; better stick with stock.
The awesomeminer or Vnish firmware is taking 2.8% fees its around 12TH/s it's too high. I think it can also be achieved by stock firmware by switching to high performance or energy mode and improving the room temp to avoid throttling, which can give similar results.

You're right about the developer commission being 3%.
I wanted to show you a little joke about pricing on the Bitmain website.
Unfortunately, standard firmware is significantly inferior to such developers, and the chip configuration mode that I demonstrated works just fine.

I read about a way to generate electricity at night, but this method requires a very large area of ​​these batteries, and the efficiency of this system is low.

"The device uses a thermoelectric module to generate voltage and current from the temperature gradient between the panel and the air. This process depends on the thermal design of the system, which has a hot side and a cold side."

It's impossible to generate electricity out of thin air. For nighttime use, batteries of the required capacity are usually installed.