@Fraoch Thank you for mentioning RTC battery. I have a Batch 4 I installed the 3.06 BIOS upgrade on so I could dim the power button and also run without battery for playing around. I had the laptop in my bag for a week and change without using it and came to find it dead.
Connecting a USB-A to USB-C cable connected to an old 5V@2A adapter didn’t light up on the right side, nor did leaving that connected for 30 minutes before attempting to then connect my framework OEM USB-PD connector to the left side. Nada. Even leaving the USB-A right side connected overnight.
Was going to read thru once more before contacting support… but saw that and was like… OK. For others’ information, I opened laptop, unplugged battery, used spudger to push RTC battery out from the left side to the right per the arrow on the board. Then I reconnected top case ribbon cable and tapped power button a few times to discharge any caps. Re-inserted RTC battery, reconnected main battery, closed laptop. Once I did that, the tip from this post worked. I gave it 10 minutes on non-PD power on the right side, then connected PD on the left, and it lit up!