Here’s the same mount that Rad sells without the branding…or it was the same one when I bought it 18 months ago
https://www.amazon.com/dp/B07GKT8FBZ?psc=1&ref=ppx_yo2ov_dt_b_product_details
This is a good one. Never rattles around and is really sturdy.
My new Moto G Stylus (big thick phone) jumped out of my plastic one and I was just crossing RR tracks; it survived. I would not fully trust any of them; I carry my main phone (w/ hotspot) in a side pocket of carpenter or cargo jeans; my (older, no SIM) ride phone is in the holder; if it pops out and breaks, no biggy. You could try an all metal one.
I had the official segway holder for my ninebot. It's complete crap if you have any kind of decent case on your phone like a normal human being.
I went with this guy, which also turns out to be a GUB brand holder like /u/Mullet161 suggested: https://www.amazon.com/gp/product/B07GKT8FBZ/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1
It's the best I've ever used. It clamps on like a vice grip to your phone and that thing is going *nowhere* no matter what kind of bumps you hit.
I've used this one for years , paired with a rubber band X thing for extra security when I forget to tighten it.