Based on an unpublished version for my Pixel 3a.

Included is the SCAD file if you want a thicker case.  Pictured is one with a 1.25mm thickness, but I've uploaded the version with 0.9mm thickness, which means the camera bar (single-layered in my photo) is missing because it's only 1.00mm thick.

I printed this in TPU. The version I have is not stretchy but is flexible enough to fit the phone into.  

When face-down, the phone sits on the cover rather than the screen, and doesn't slide off the desk as easily.

edit: Made the USBC hole larger; my new cable has a larger plug.

2022-10-26: New version 02 that's a bit taller.  

My phone landed flat on its face onto tiles, and it cost half the purchase price to get the screen replaced.  The edges are now 1mm higher than the screen+protector, to try to avoid a repeat.  

Also there's now a ramp either side of the camera bar so you can have a thinner overall case but it still matches the camera bar where it meets.  It's on the inside so it prints flat.

Finally, moved the camera bar hole up 0.5mm so it fits better.

2023-04-08: v4. My new filament, eSun TPU 95a, is more flexible than my previous white TPU, which meant the sides were floppier than I like. I've increased the sides thickness to 0.9mm, and kept the back at 0.5mm.  Also moved the power/volume hole up by 1mm to better match the buttons.