Installed 2nd GPU (RTX 2080 for Windows), Windows boot Manager does not show up in the boot options (F11)

Hello, i've just installed a 2nd GPU (Zotac RTX 2080) on my 2nd PCIE slot on my Motherboard, MSI Z390A-PRO. Prior to the install, i could still boot into Windows. But after booting it up, the windows boot manager did not show up. However in Mac OS, i could see my Windows SSD drive being mounted

I did not do anything post installing the GPU into my motherboard..

Please help!

Opencore 0.5.9
Mojave OS
Mobo: MSI Z390A-PRO + i9 9900k
GPU: RX580 (First PCIE Slot)
2nd GPU: Zotac RTX2080
Ram:32Gb Corsair Vengeance