This is a 2 piece dash mount designed for a Pixel 2 (not XL) inside a Caseology Parallax case. It shouldn't be too hard to adjust the dimensions for other cases and the SketchUp project file is included.
This is in 2 parts to make it easier to print and to allow custom angle adjustment.
It's meant to be fixed to the top of your dash using 3M Exterior Mounting tape which I find works really well in and on vehicles, and it's removable without leaving behind residue or marks.
Added a variation with a cutout where the charger goes so that you can plug in your phone outside of the charger and then pop it in afterwards. This model is also 0.5mm wider and 0.5mm smaller from front to back, which I found fit better.
Added another variation where there's no bottom at all.