MTKView compositing one UIImage at a time - swift

Question

I have an array of UIImages that I want to composite via an MTKView using a variety of specific comp modes (source-over, erase, etc). With the approach I describe below, I find that the biggest overhead seems to be in converting each UIImage into an MTLTexture that I can use to populate an MTKView's currentDrawable buffer.
The drawing loop looks like this:
for strokeDataCurrent in strokeDataArray {
let strokeImage = UIImage(data: strokeDataCurrent.image) // brushstroke
let strokeBbox = strokeDataCurrent.bbox // brush bounding box
let strokeType = strokeDataCurrent.strokeType // used to define comp mode
// convert strokeImage to a MTLTexture and composite
drawStrokeImage(paintingViewMetal: self.canvasMetalViewPainting, strokeImage: strokeImage!, strokeBbox: strokeBbox, strokeType: strokeType)
} // end of for strokeDataCurrent in strokeDataArray
Inside of drawStrokeImage, I convert each stroke to an MTLTexture like this:
guard let stampTexture = device!.makeTexture(descriptor: texDescriptor) else { return }
let destCGImage = strokeImage.cgImage!
let dstData: CFData = (destCGImage!.dataProvider!.data)!
let pixelData = CFDataGetBytePtr(dstData)
let region = MTLRegionMake2D(0, 0, Int(width), Int(height))
stampTexture.replace(region: region, mipmapLevel: 0, withBytes: pixelData!, bytesPerRow: Int(rowBytes))
with all this in place, I define a vertex buffer, set a commandEncoder:
defineCommandEncoder(renderCommandEncoder: renderCommandEncoder, vertexArrayStamps: vertexArrayStamps, metalTexture: stampTexture)
and call setNeedsDisplay() to render. This is happening for each stroke in the above for loop.
While I get ok performance in this approach, I'm wondering if I can squeeze more performance somewhere along the way? Like I said, I think the current bottleneck is in going from CGImage -> MTLTexture.
Note that I am rendering to a defined MTLTexture metalDrawableTextureComposite which I am blitting to the currentDrawable for each stroke:
copyTexture(buffer: commandBuffer!, from: metalDrawableTextureComposite, to: self.currentDrawable!.texture)
Hopefully this is enough detail to provide context for my question. Also, if anyone has ideas for other (GPU/Metal-based hopefully) faster compositing approaches that would be awesome. Any thoughts would be appreciated.