RahmedMobo = B450-A pro max
Usb = 64gb (56gb shown on file explorer) exFat (only option to format besides NTFS)
This is probably your issue, the filesystem almost definitely has to be FAT32, and you'll want to use an MBR not GPT. Most people recommend a 16GB or smaller drive, but 64 will probably be fine and you could always try making the partition smaller than 16GB if it still doesn't work. Google should be able to walk you through how to get it formatted correctly. It's also worth trying a USB 2.0 drive if you're using a USB 3 one.
RahmedMobo = B450-A pro max
If worse comes to worst and I find it's bricked, is there a recommended better motherboard I can buy?
You'll never need to buy a new motherboard in the case of a corrupted bios, in the absolute worst case you can use an external SPI programmer to flash a working bios firmware onto the chip, it's a quick and easy process if you have the tools available or know someone who does. If not, any repair shop will also be able to do it for you.