@mdubnick - have you considered the possibility of exporting your TheBrain corpus as a Markdown or other file, and importing the works into a Tinderbox project file? You might then use Explode to break it down again into atomic Notes in Tinderbox.
Markdown adapts well to Explode command in Tbx. Not sure how internal links would fare through the breach. That may be a challenge or an opportunity for a fresh outlook, depending.
There is some info on exporting TheBrain data files here:
Exporting a Brain to a Markdown document - TheBrain Forums.
If nothing else, may be a useful exercise in seeing your brain in a different setting, so to speak. Am also reminded of @mwra’s recent comment about Tinderbox’s dexterity in assisting primary quantitative analysis on big data; any database with 10’s of thousands of Notes seems fair game for Tbx 