BIOS does not always detect SSD (Help please)

[-TheWeeknd-]

I've recently built my first PC. The specs are as follows:
MOBO: Asus Prime Z490-P ATX
CPU: Intel Core i7-10700K
GPU: Gigabyte GeForce GTX 1660 Super 6GB
PSU: TX750M — 750 Watt 80 Plus® Gold
RAM: HyperX Fury DDR4 3600MHz CL17 (2x8GB)
SSD: Samsung 860 EVO 1TB


I've been having a weird issue with booting. My pc will often boot into BIOS without seeing my SSD. I turn the pc off, uplug the power cable and plug it back in. Sometimes it will boot to the SSD, and sometimes it will still throw me into the BIOS forcing me to repeat the process.
What I've tried so far:
Resetting CMOS, changing the SATA cable, trying all slots in the SATA power cable (all of them work, I have 5 fans connected to a controller that powers from SATA and I tried every slot).

I've been speculating what the issue might be but I don't have the knowledge to conclude what the issue is. Could anyone please help me?

Everything else works, all the fans and the RGB. I can even play games such as Red Dead Redemption 2 on ultra settings with no issues.