the stock 460w psu you have is probably non modular, whereas the higher power Dell psu are all modular.  You plug one of the EPS 8 pin cable connector of the modular psu into the mobo gpu_pwr socket. according to AW psu guru Cass, Aurora models (R5 & newer) share the same PSU (&/or PSU pinout = can share cables) with Area-51 models (R2 & newer), where the 850watt Bronze/Gold, 1000w & 1500w PSU all have the same front panel layout & same front panel pinout, making both the PSU chassis & PSU case cables all interchangeable. [IMAGE] use basic online psu calculator to estimate your psu upgrade need. for i7-9700, RTX 3090,Load Wattage: 538 WRecommended PSU Wattage: 588 W so upgrade to R9 stock 850w psu already gives you plenty power. [URL]  
      Dell R10-12 PSU (D1000EGM-00)      
Aurora R9, PSU Upgrade Questions