Trackpad and KB unresponsive, and replacing trackpad cable didn't help

Hello,

I have an Early 2015 MBP 13” Retina that very suddenly experienced complete loss of trackpad and keyboard function. I went ahead and replaced the trackpad cable with one ordered from ifixit, but doing so did not restore functionality.

Plugging in a USB keyboard and mouse work fine, and, in doing so, I have been able to reset the NVRAM and delete some of the .plist files that are often recommended to fix the issue. I was also able to use the built-in keyboard to do an SMC reset (which also didn’t help). I ran some diagnostics with CoconutBattery, and it appears that the battery is in good condition. Additionally, the MBP has not been exposed to any liquid (other than very light cleaning with cotton swabs and 91% isopropyl alcohol).

One thing I noticed is that, unlike others with similar problems with the Early 2015 mode, my trackpad and keyboard are unresponsive when booting in safe mode, and I can only boot in safe mode with an external keyboard. The issue was also very sudden, as I have not experienced the sporadic functionality loss that others have reported. Additionally, resetting the NVRAM was only possible through Terminal as my MBP did not recognize the keypresses on boot.

I am currently working on flashing Ubuntu to a USB drive—I’ve read some have been able to use the trackpad and keyboard outside of MacOS. I’ll make an edit after I test this.

Are there any other steps I can take to isolate the issue? Should I try another trackpad cable (in case the one I ordered was DOA)? Or should I start thinking about replacing trackpad?

Edit: I was able to create an Ubuntu USB boot drive. I was able to use the trackpad in Ubuntu, but not the keyboard.