The battery was dead, I could open the doors with the key, but no power meant that I could not release trunk lid with key in door.
Also, key release in trunk lid above license plate plate did not work.

Opened rear center armrest. Used screwdriver at the top of the plastic cover, pushing it down to release it to reveal interior of trunk.

Yellow emergency release is all the way back on the lid. I couldn't reach that far. So I took a 3' piece of 1/2 inch diameter plastic pipe. You could also use wood maybe 3/4 square as well.
Drilled 2 holes about 1/2 apart at an angle about 45 degrees. Used 2 - 2inch wood screws (because they have a coarse thread that could grip the plastic handle). From the side it looks like a claw on the end of an arm.

I could see the release with a flashlight. I reached in and used the "claw" to catch the release in the neck above the handle. Slight pull and trunk was released.

Hope this helps