My wife was balancing her phone on the handle bars, I knew I'd be buying another phone if I didn't come up with a solution. So here it is:
Printed at 10% infill, with supports. I used tree supports, touching buildplate.
I ended up putting double back tape on the bottom to secure it too the handlebars, but it will hold the phone without it (just not as secure).
The author marked this model as their own original creation.