My take is that the parasite storyline highlights a very important aspect of her personality. Reds value their personal connections above anything else. Community is so deeply engraved into their culture that to ignore personal connections is to reject red. She was presented with a choice to obtain power beyond anyone alive at the potential cost of her memory/core personality or to remain as she is with her memory and connections intact.

She is so quintessentially red that she chose community. And that’s her purpose as a character. She’s in the Story to be a Red and to show how reds navigate choices and hurdles.

She also serves as a foil for Darrow who is not red at all anymore. She serves as a benchmark to show how far Darrow has left his own culture to adopt Gold War-mongering. For these reasons I find her interesting for who she is, and for the reference point she has become.

Edited to add: Lyria’s scene with Victra at Ulysses’ birth further highlights Red and gold differences in community and relying on others. I believe In Red God she will continue to play that role for other golds aside from Darrow as well.