New build, gpu / external gpu questions

Ok so, I have some parts sitting around and I am gonna put them together. Amd build, am4 but that's not the concern. I have a spare gpu I was going to slide into one of those docks that I can get oculink out of.

My question is...if I set up an egpu dock ( the idea is to use it with one of my handhelds) can I also run the oculink into that sffpc? Or could I just get a long pcie extension cable and feed it out of the case to use sometimes? I'm think small case with no room for gpu inside. Technically I could use an nvme slot to make it oculink ready I suppose.

I searched to see if this sort of thing has been addressed recently but didn't see anything in specific to what I am considering. My search skills could also be lacking. Anyone have something like this set up?