Unfortunately, a seemingly simple problem that might not have a simple answer.

I run my system with 2 monitors connected via DP, and 1 via HDMI, RTX 2060 video card. The two monitors are 27" 1440p LG monitors. The HDMI cord is connected to an HDMI signal splitter, and from there to an LG TV. Historically this has been a non issue, I duplicate the signal from the TV and one of the monitors to watch shows. For the last two weeks, my computer detects the TV, but no longer displays on it. If I restart in safe mode, the default monitor to use is the TV, and the signal works with no issue. Also, when re-starting the computer, all BIOS information shows up on the TV exclusively, but after getting to the Windows login screen, the TV goes to no signal and only the monitors work. I deleted all drivers with DDU and installed fresh and updated ones, and that didn't fix the issue.

Two different HDMI 2.1 cables have this issue (also happen to be the ones snaked behind the wall), but when I switch to a 1.2 or 1.3 cable, it works with no issue. I found it so unlikely that two cables are giving the same issue at the same time, but I'm out of other ideas of how to fix this

The only thing I haven't done because I don't have a second one is to switch out the HDMI signal switcher, but because that works with the older cable, that also seems unlikely to be the issue

Anything else to try? I really would prefer not to fish new cables behind my wall, it's a pain in the ass