The controller is only designed for 4 fans, which are already connected. I found information that you can theoretically install one more per channel and get a total of 8 fans, but I didn't take the risk and connected the extra fans to the motherboard. If you need ARGB, you should buy a separate high quality controller.
I was able to connect 10 of them without any problem, the connectors of the 4 supplied are duplicated to make it possible to go up to 7 with the 3 from the AIO. I then bought 3 Deepcool fans, also supplied with splitters, and was able to connect them. Power supply and RGB are split!