If you control the underlying data, I must reccomend Amazon Ion! Its text format is a strict superset of JSON, but they also maintain binary format that will round-trip data and is designed for efficient scanning. There's even prefixed annotations if you want them :)
It also specs proper decimal values, mitigating the issues presented in the OP.
It also specs proper decimal values, mitigating the issues presented in the OP.
https://amazon-ion.github.io/ion-docs/