I lashed out and bought ecycles, the RTX version. Not cheap given that the AUD is quite a bit down on where it was a year ago. Also it has some limitations, at least the RTX version does. I’m working through the Material Guru course on Udemy, and he uses the AO node quite a bit, as here. Edge rust is pointiness but proximity to other components is AO. This is a current limitation of Optix, and I couldn’t even render it with the RTX version of ecycles. However the non-RTX version did render it 50% faster than standard Blender. I did try the RTX on some of my recent landscapes and it certainly is fast on those.
I must admit this course is giving me a good grounding in the features of node editing that I’ve had a lot of trouble with in the past. Extensive use of Math nodes for a start, and quite a few nodes I wasn’t familiar with. I even discovered there actually is a UV input node, and to think I’ve been trying to use Attribute nodes to specify UV maps.
I’m hoping to become as competent with the node editor as I was with Photoshop for 2D images. I got pretty good at that by the time I gave up stock photography. Mind you, I did do a lot of study and got a lot of practice with very critical judges.