I've designed a third-person view arm specifically for the ImpulseRC Apex frame and the Insta360 Go camera. I've also combined it with a compatible cam mount available at Thingiverse Link. The mount is 3D printed in TPU, while the arm is printed in PETG or PLA for added durability.
 

You can see the first test on my Instagram, though it was a bit shaky. I plan to try PLA or a dual-arm design for smoother results in the future.