And you think my reading was convoluted!

I don’t see the subsequent appearance before the people in Hebrews, and you don’t provide any evidence. Isn’t it rather odd that this aspect of the high priestly role doesn’t show up in the most elaborate development of the motif that we have in the New Testament? Or am I missing something? It is never a good idea to read into figurative language (metaphor, analogy, typology) more than is clearly indicated or required by the argument. The fact that you have to conflate the two second appearances (boy, this is confusing) into one does not inspire confidence in your argument.

The language of ‘appearing’ that we have in Hebrews doesn’t seem to belong to the OT narratives - it suggests a visionary appearing. There is also no reason to interpret the ‘appearing’ of the parousia texts that you list as an allusion to the activity of the high priest, whereas in several of them there is explicit reference to the ‘kingdom/judgment’ idea that we have the Son of man motif.

There is nothing in John 20:17-23 to suggest that John is thinking in terms of a high priestly typology. There are certainly some oddities here, but there is insufficient reason to think that they are to be explained in this way.

There is nothing to identify the souls under the altar in Revelation 6:9-11 with the goat that is killed on the day of atonement, though I agree that there are sacrificial overtones here.

There is no allusion to the scapegoat in Revelation 17:3. There are all sorts of problems, not the least being that the scapegoat bears the sins of others, ‘Babylon the great’ (which I think must be a pagan power) is destroyed because of her own sins.

In other words, I don’t think the NT uses the high priest typology as a controlling metaphor in the way that, or to the extent that, you think it does.