My understanding is that mnesia is sort of a relic. Really hard to work with and lots of edge / failure cases.

I'm not sure if it should be salvaged?

They are in the process of migrating away from it https://www.rabbitmq.com/docs/metadata-store

Mnesia along with clustering was a recipe for split brain disasters a few years ago I assume that hasn't been addressed.

I have only worked with a product that used it, so no direct experience, but one problem that was often mentioned is split-brains happening very frequently.