There is a user manual which in theory contains all the information required to write your own driver. It did for the DW1000, it wasn’t very clear on how some things worked but it did at least tell you what you needed to know to make things work.
However the DW3000 manual has a number of sections where it tells you to refer to the driver source code for details of how to perform an operation. The driver source code (the old version that was released before it became binary only) for those functions would change registers that weren’t listed in the manual or would set bits to values that the manual claimed were invalid.
In other words the documentation is a mess, has been for several years now and qorvo don’t seem to have any interest in fixing it.
To be honest the only reason I didn’t dismiss the DW3000 out of hand was because we already had a DW1000 product up and running. If I was starting from scratch I’d be looking very hard for an alternative part with any semblance of support.
Another user has been attempting to assemble the information missing from the manual. Details can be found in this post: "Missing manual" for register-level access to DW3000 (without using API)