

I think pretty much any mosfet / h-bridge / motor control board with pwm should do.
If you have those 4-wire fans with a pwm input that accepts 3V3 logic, you might even be able to attach them directly to the ESP:
But that’s not all fans, I had some mixed results with that.
I think after initial installation, you open a browser with the post-installation step and configure a username and password there. I’m not entirely sure, it’s been some time since I did it. But depending on installation method, I don’t think it has a provided password.
General password advice: Check caps lock, and if you use like a German keyboard if ‘z’ and ‘y’ are swapped.