Fixed

The repaired piece is barely visible at the bottom

Here's a quick peek at the repaired line. It's not perfect but it will be fine once the colors are added and it is likely that tiny gap on the left of the repair will close once the wood swells a bit after printing for a while. (I only hastily pulled 4-5 copies to check out how cleanly it will print).

I won't post the finished keyblock impression. As most of my prints are defined by the drawing, if I show it now there won't be any mystery later.
I printed up a few onto watercolor paper with sumi so I can test out some color ideas.
I'm not there yet though as none feel "right" nor mesh well with the idea I have in my head.