See https://www.printables.com/model/623067-q-lock-ball-mount-adaptor for ball mount but will be compatible with the attachment system that rhymes with fod lock (untested on branded quadlock)

Aptly named BFP “Big Freakin Phone” this holds BV990 Pro (including its own soft case), there is also supports to glue separately to stop splits along the layer lines.

I've dropped it a few times in the case and its normally fine, worst I had is a chipped corner.

There is a little bit slop in the mechanism but hasn't let me down yet and also functions as a bit dampening