I think I've tried everything I can on my own (see below) but no improvements. Tomorrow I'm gonna try the other 2080 and probably confirm that I have a dead card while the other one works fine.
Cool GTX
What OS are you using?
Windows 10
Cool GTX
1) Make sure the PC is unplugged - the MB always has power even if Windows is shut down (soft off)
Just attempted this again: turned off computer, switched PSU to off, unplugged PSU, long-pressed power button, and then turned everything back on.
Cool GTX
2) That you are grounded, (no static discharge = ESD procedures)
Check.
Cool GTX
3) Everything is fully locked into place PCIe slot & PCIe power
Check.
Cool GTX
4)Turn Fast Boot = OFF (in the MB BIOS), Before you change any hardware (you need the MB to look for new hardware)
Forgot about fast boot and also didn't know MB looks for new hardware with Fast Boot off. Fast Boot is off by default but I had turned it on at some point. When I updated all MB drivers and also flashed the BIOS, it went back to default (off).
Cool GTX
5) Use known good video cable & monitor
Check.
Cool GTX
6) Have the appropriate Nvidia driver already downloaded & read to install - OR - reinstall if need be
Updated as part of my attempts inside the OS earlier on, but the card never gives me an output, and it doesn't sound like it's booting all the way up because pressing the power button turns it off almost immediately (turning off from OS takes a bit longer).
I really appreciate all your help with this, it's been invaluable! If nothing else, I've learned what not to do moving forward (had no idea about using other PSU cables, and my experiences with Best Buy PSUs is that the cables for one PSU don't fit any other - except apparently the EVGA PSU's VGA cables I initially used).
I'll report back tomorrow but I think we already know it's probably a dead card.