Applying shader effects to another? Approximated depth buffers?

I was wondering if it is possible to apply one shader's effects to another shader using reshade? Like if I wanted to, say, apply xBRZ4x to SMAA's edge detection, would that be possible?
If it is I would love to know how. I'm not good with programming though, so if it's not a thing that reshade can do, I can't make a shader that can do that even if I tried.

Also, is it possible to approximate depth buffer values from a video/still image? I'm asking because I managed to get reshade to work on my capture card software that lets me stream my Switch to my computer. Obviously reshade can't obtain a depth buffer the traditional way as there is no depth buffer to be obtained through a generic video feed, but if there is an approximation method out there, I would be happy to test it out. And before you say it, performance is not a concern for me, as I imagine that if it were possible to approximate depth buffers, it would cost enormous amounts of CPU overhead.

Thanks in advance