How to change the Coordinate reference system/projection in react native maps?

Question

Can react native maps coordinate reference system be changed? So far, there is nothing that points to it. If the coordinate reference system/projection of the react native maps can be changed?

The requirement is we need an iOS and Android app that heavily uses coordinate reference system not based on 3857, the tiles from the server are based on British National Grid (227700). Other options are costly or induce unnecessary complexity.