Any thoughts on the Alex RSD30 rim?
https://alexrims.com/products/rsd30/
Looks the exact same as the Origin8 Bolt, both claim 400g, 30mm height, and same 19mm internal width. Seems like one of the lightest aluminum rims I've found which could be worrisome but Alex usually makes a decent rim though usually on the heavy side.
Probably pair it with Profile Racing hubs since they're a decent price and come in purple for my daughter, not to mention their bearings are highly regarded as fast in the BMX race scene.