I can only boot to windows through the BIOS. This is a problem that I have had before and magically fixed, I really don't know how. I just installed a new m.2 Samsung 970 EVO Plus and now the issue is back. So far, I have moved windows and the contents of the 860 EVO SSD to the m.2 and wiped the 860 EVO SSD. This deems it not a storage issue. I have also tried my old PSU so it's not power. The only resolution I have found is removing half of my ram will bring it to boot straight to windows sometimes. However, I feel like this isn't the solution since I'm able to boot windows through the BIOS with all 16GB fine. Any and all help will be greatly appreciated!
Part list from pc part picker
CPU: Intel Core i7-6700K 4 GHz Quad-Core Processor ($360.00 @ Amazon)
Motherboard: Asus PRIME Z270-A ATX LGA1151 Motherboard
Memory: Crucial Ballistix Sport 4 GB (4 x 4 GB) DDR4-2400 CL16 Memory
Storage: Samsung 860 Evo 250 GB 2.5" Solid State Drive ($94.99 @ Amazon)
Storage: Samsung 970 Evo Plus 1 TB M.2-2280 NVME Solid State Drive ($139.99 @ Adorama)
Storage: Seagate Barracuda Compute 2 TB 3.5" 7200RPM Internal Hard Drive ($49.99 @ Amazon)
Video Card: MSI GeForce GTX 980 Ti 6 GB GAMING Video Card
Power Supply: Corsair RMx (2018) 850 W 80+ Gold Certified Fully Modular ATX Power Supply ($129.99 @ Corsair)
Part list from pc part picker
CPU: Intel Core i7-6700K 4 GHz Quad-Core Processor ($360.00 @ Amazon)
Motherboard: Asus PRIME Z270-A ATX LGA1151 Motherboard
Memory: Crucial Ballistix Sport 4 GB (4 x 4 GB) DDR4-2400 CL16 Memory
Storage: Samsung 860 Evo 250 GB 2.5" Solid State Drive ($94.99 @ Amazon)
Storage: Samsung 970 Evo Plus 1 TB M.2-2280 NVME Solid State Drive ($139.99 @ Adorama)
Storage: Seagate Barracuda Compute 2 TB 3.5" 7200RPM Internal Hard Drive ($49.99 @ Amazon)
Video Card: MSI GeForce GTX 980 Ti 6 GB GAMING Video Card
Power Supply: Corsair RMx (2018) 850 W 80+ Gold Certified Fully Modular ATX Power Supply ($129.99 @ Corsair)