Graphics card suddenly failed... again

TLDR: 1660 died a few weeks ago, have been using a 720 since then, got a 3070 today and now the 720 died.

Funny to be here again. I made a post from a few weeks ago about sudden GPU failure and received a lot of helpful responses. Here's a recounting of what's happened since then.

- Bought a new PCIe cable from eBay. Did not work
- Asked friends about a new graphics card. They recommended I buy a 3070. Ordered one off of eBay.
- 3070 arrived in the mail today. Great condition. Sat it into my PC and it works like a beauty. There's only one problem...
- I didnt realize this at the time of ordering, but it only had one HDMI port. I have two HDMI monitors and a VGA monitor. I guess I take the HDMI and VGA combo on my older gpus for granted

So here's what I decided to do... I kept the old 720 plugged in, and my two side monitors are now connected to the 720, while my middle monitor is connected to the 3070's single HDMI port. Do note that the two monitors now connected to the 720 are the two monitors that were connected to my 1660 when it failed; the now-middle monitor is an extra.

This setup worked great for about 5-10 minutes, then suddenly both of my side monitors (the ones connected to the 720) both lost signal, leaving only the middle monitor connected. No signs of failure beforehand, just like with the 1660. Now I'm left wondering... Could it be that the 720 is old and its time has come, or am i feeding cats to the coyotes? I am not running my computer until this is decided, in case its a faulty component destroying my computer.