The problem with using RenderDoc is that it doesn't capture ANGLE GL function usage, only the underlying D3D calls. So you have to correlate the high-level GL API calls with whatever ANGLE is lowering them to yourself.
It would be nice to have a native D3D11 backend (and D3D12, and Metal, and Vulkan) someday, but that day isn't today. gfx-rs, or wgpu-rs, looks promising as an abstraction layer over all of these APIs.
Have you spoken to baldurk about this? Since RenderDoc has GL support and it captures with Detours, in theory with some work it should be able to capture at a level above ANGLE. Not sure if that'd be helpful, but I expect maybe.
Alternatively, could you emit markers at or above the Angle level to provide an easier to understand RenderDoc trace?
You can compile ANGLE with ANGLE_ENABLE_DEBUG_TRACE=1 to get a log of all GLES calls to ANGLE's frontend. It's not the same level of detail as RenderDoc, but it's something.
It's opensource with MIT license. I wouldn't expect too many issues supporting such use case, given RD's support for normal OS-supplied GLES. I would only expect complications if you'll try capturing both layers at the same time, GLES between your app and angle, and D3D between angle and d3d11.dll.
It would be nice to have a native D3D11 backend (and D3D12, and Metal, and Vulkan) someday, but that day isn't today. gfx-rs, or wgpu-rs, looks promising as an abstraction layer over all of these APIs.