spertum
When you write that backlight seems to have failed, do you mean that you have a pixel 7a whose display is now entirely dark?
Just a small clarification because according to my knowledge - and unless that phone was heavily modified - that model should have an OLED display, which by design work via self-luminous pixels. (Unlike many LCD screens that are composed of a separate (back-)light shining trough a crystalline matrix which forms the light into an actual image).
Regarding the actual issue (assuming we are talking about a dead OLED display and everything else is working) I see 2 abstract possibilities:
- Navigating completely blindly according to a list of keypresses. I think s.o. familiar with the 7a would hopefully be able to provide such info. It might however involve guessing and targeting invisible regions on the screen. Additional complications may arise from configurations like scaling changes that cause positions of menu items to differ compared to unmodified graphene.
- Partial solution: Somehow getting the 7a to project its screen content to an external display. Theoretically, there are options for this (see https://support.google.com/pixelphone/answer/2865484 ). However, even that would probably involve at least some blind keypresses etc (though maybe less than for reaching OEM unlock option) and probably wouldn't help for the steps when GOS doesn't run.
I am sorry that I can't offer more for now.