If the fans don’t have splitters for their ARGB, you can always buy a
https://www.overclockers.co.uk/kolink-argb-1-6-splitter-cable-30cm-cm-00k-kk.html
6 fans is the maximum I’ve ever connected to a port.
As others suggested, a powered hub may be an option, and price wise, not far from the splitter option
https://www.overclockers.co.uk/deepcool-sc700-argb-12-port-hub-fg-008-dc.html
There’s also a version of this hub with PWM ports.
Personally I used to control all ARGB with one controller, but fans I prefer to group them according to their position, to fine tune noise/airflow.