I have switched cables and power adapter to make sure power isn't an issue.

I've made sure that what I typed in wpa_nf is correct, letter by letter (in fact, I compared it to my other server Raspberry Pi 4's wpa_nf, which worked, to copy exact letter by letter). I've placed my raspberry pi directly next to the router, so range isn't an issue. I made sure that I am connecting to the 2.4ghz wifi, not the 5ghz. When revisiting the SD card, these two files are gone, but I have made sure to re-add the files again. Neither of them are able to connect to my wifi router. I have both downloaded, drag, and manually place an SSH file and a wpa_nf file onto my SD card, and used the CTRL+Shift+X hotkey option when flashing my SD card. Both are not able to show up in my wifi router admin portal. I initially tried the Raspberry Pi OS (32-bit) option, before trying the OS Full (32-bit) version. I used a Raspberry Pi Imager v1.6.2 to flash onto my micro SD card. I followed couple youtube tutorials on starting it up headless. I will create a new post that will ask a slightly different question, now that I abandoned the headless setup. For now, this would be my temporary work-around. Unfortunately I do not know exactly why, and I wanted to know why. UPDATE: Semi-Solved.? I've plugged in a USB Dongle onto my Raspberry Pi Zero W, and it had finally connected to my wifi router.

Pi zero w setup