Just throw away the inverted TIFF and keep the original RAW file. I get a bunch of TIFFs in Lightroom all the time, because this dumb thing can't really do much anyway, it's just an NLP launcher.

Every time I edit a file in Affinity Photo I end up with yet another temporary TIFF.
What inverted TIFF?
Maybe my understanding of how Negative Lab Pro and Lightroom work is all wrong?
As I understand it, all edits to RAW files in Lightroom are kept as a set of instructions that are not actually applied untill/unless the file is Exported, right? So yes, if you "Edit with..." Affinity Photo, or Photoshop, or any other bit editor, that involves generating a TIFF. I assume the NLP conversion is like any other edit in Lightroom - that is, a set of instructions and not an actual duplicate file - unless I tell NLP that I want it to create the TIFF, right?
But the vast majority of the editing I do can be done entirely in Lightroom, so I almost never* have a TIFF in Lightroom that duplicates a RAW file. And that's the way I like it. A RAF file from 16 MP Fuji camera is about 33MB. But if I tell NLP to make a TIFF copy, that TIFF copy is 90MB. So if I keep the RAW, what was 33MB is now 123MB.
* Exceptions: If making camera copies of b&w or slides I usually start in Photoshop and get the file pretty close to how I want it before taking it into Lightroom as a TIFF for cataloging, captions, keywords, etc. Because all the heavy lifting was already done in Photoshop, I don't feel the need to keep the RAW file for those in Lightroom, because only minor future edits are likely. I will do the same with camera-copies of my color negatives if I can find some way to do the color inversion that I can live with and that can be done outside of Lightroom. Still trying out some of the non-Lightroom options mentioned here.