This is a remix of Pappadakko's redesigned dashcam mount for the 5th-gen 4Runner to work with the U3000 rear camera. I printed it in ABS to help prevent warping from heat in the summer.
I recommend installing the camera on the passenger-side headliner retainer instead of the center mount. This puts the camera closer to the window area cleaned by the wiper.
It was a little tight getting the end of the cable through the hole in the headliner for the camera but it did fit.
I mostly followed this guide Dyslexic_Nerd made:
https://www.reddit.com/r/4Runner/comments/w3tyk2/i_made_a_writeup_for_a_painless_clean_install_on/
https://imgur.com/a/2020-4runner-front-rear-dash-cam-installation-UwGt3mN
A few things I did different from Dyslexic's install guide was,
The author remixed this model.
Elongarted the part in height and width to better fit the U3000 rear camera.
I added a 20-degree slope for the camera to mount to since the U3000 only has a limited amount of tilt adjustment.