Omit $type tags when writing json

[ikr]

My use case is rather weird. I must skip all the $type JSON values generated for Scala 3 enum case-s.

For example, given

enum FinancialInstrumentQuantity1Choice {
  case UnitDecimalNumber(unit: BigDecimal)
  case FaceAmtImpliedCurrencyAndAmount(faceAmt: BigDecimal)
  case AmtsdValImpliedCurrencyAndAmount(amtsdVal: BigDecimal)
}

instead of:

{"$type":"FaceAmtImpliedCurrencyAndAmount","faceAmt":"1337.002001"}

I'd like to have just:

{"faceAmt":"1337.002001"}

I don't care about parsing it back into an enum at this point. But, if I would, I'd still be able to recover the concrete case by the value attribute name: unit, faceAmt, or amtsdVal.

So, the main question is: how do I omit all those $type values when write-ing JSON?