I really really like mobx-state-tree (which is way different from just mobx). I'm not sure where I'd use the Context API over MST, but I'm currently toying with comparing both. Offhand, MST seems to be friendlier to Typescript.
I've used flux, redux, mobx, context, combinations of those, and I think I finally found something that will stay.
If you haven't tried it, I highly recommend it!