I got my hands on a GPS accessory recently that I’m quite impressed with. Rec-Mounts is a Japanese company that makes TONS of mounting accessories for lots of applications. They sell some of their products on Amazon, thankfully, because it looks like ordering through their website directly could be difficult.
Their products are top notch.
I started out with their Type 10 stem spacer mount. Couple things I like about the products this company makes. Namely, their modularity. They use a number of fairly standard mounting systems so a lot of their stuff is interchangeable. The Type 10 mount has a GoPro adapter as the adjustable pivot. So I can pull the 1/4 turn adapter off and put something else there to mount a different computer.