Mac Mini Late 2014 Won't Boot

My Mac Mini (2014, fusion drive) started to constantly freeze and require hard restarts. Soon after it started having boot problems too. I don’t remember the specifics of what would happen at boot, but ultimately I was only able to boot into safe mode a single time. I haven’t been able to get it to boot since.

Currently it powers on (front led turns on), chime sounds, external monitor turns on but screen is blank.

Powers on to blank screen.

Responds to command to reset PRAM (more chimes), but doesn’t help.

Fan works and appears to run normally while device is on.

I replaced the HD (main SATA portion of fusion only). Probably should have checked here first as it didn’t help or change symptoms in any way. Side note, I was unable to access the old HD with my other mac…it didn’t even register that there was a drive connected when using the device I used to format and install MacOS on the new HD. I was expecting either the new drive to fix the problem or to be able to easily retrieve my data off the old drive. Super annoying.

One final note, my external keyboard lights up on power up and I can get the caps lock light to toggle on/off for the first few seconds (during and immediately after chime). After that point, power appears to get cut to the device. Also, plugging in a monitor after that point results in nothing happening...the monitor doesn’t detect there is even a device connected at that point. The front led and fan continue to stay on until I force turn off the device by holding down the power button.

Any advice would be greatly appreciated! Thanks!

EDIT: I have tried all startup key combinations with no result. Option-Command-P-R (NVRAM/PRAM reset) was the only combination that the machine appeared to respond to, but it ultimately had no effect. I have verified that the monitor and monitor cable work with another computer. Besides the initial startup chime, the device makes no other beeps or noises.