[Video] Raspberry Pi 5 not booting or going to diagnostic screen? Led Lights are Red, Green, Solid R

How can I reflash the firmware/bootloader to see if that's the issue? My other 5's work fine with same power supplies (tried multiple supplies). I removed all connections including the SD card to see if it entered diagnostic mode; it didn't. Here's a video of the status LEDs. Led Status Lights do not match anything on the stickied thread in the Pi troubleshoot forums. https://streamable.com/xxg0w3