So, I'm just as dumb as I look. Placed the splitter into the clear part that says CHA_FAN and boom, it worked. Apologies for wasting everyone's time here. Thank you for your help.
Ah, that makes sense. I'm relatively new to doing this sort of stuff on my own. If it doesn't go into the RGB header, then where would the fans insert into?
Build:
Corsair 4000D Airflow Case
ASUS TUF B450-PLUS Gaming ii
Ryzen 5 - 3600x
Nvidia RTX 3070
Corsair Vengeance RGB PRO 32gb (16 x 2) DDR4 3600MHz
Corsair RM850x 850, 80 Plus Gold
Corsair AF120, 120mm (Chassis Fans)
Okay so, I replaced my old PSU (VS650) with my new RM850x. The PC boots and...