I am searching for a nice serialization format which offers a binary and plaintext representation and which allows to specify validation rules.

It seems like reinventing a wheel. And the wheel seems to be ASN.1 as far as I understood.

Could you maybe guide me from your experience why many other serialization formats were invented and why not everybody uses ASN.1 where you already get all kinds of RFCs (e.g 5280) or ISO standards on how to define for example a representation of a TLS certificate and and such.