Followed the setup wizard close this time, and my Octopus Pro was flashed, and RatOS found the board as intended.
Next I should install V-Core 3 Printer in Mainsail, but after doing so, I get a MCU connection error.
Is this due to:
(1) missing settings in the printer.cfg file?
(2) or the error described in the docs when updating Klipper (and you have to reflash the motherboard)?