Determine singleton type parameter in match case

Language Design
1

Scastie (scala 3.5.0-RC2) with -source:3.3:

import compiletime.{erasedValue, constValue}
// java apis
trait S
class I extends S
class Str(s: Int) extends S
class F[A <: S](s: A)
// scala wrapper
opaque type Sized[N <: Int] <: F[Str] = F[Str]

type SS[T] <: S = T match
  case Int => I
  case Sized[t] => Str

transparent inline def s[T]: SS[T] = inline erasedValue[T] match
  case _: Int => I()
  // error: cannot reduce summonFrom with
  // patterns :  case given ev @ _:ValueOf[Nothing]
  case _: Sized[t] => Str(valueOf[t])
  // error: Nothing is not a constant type; cannot take constValue
  case _: Sized[t] => Str(constValue[t])

@main def run() = s[Sized[5]]

My aim was to create a Sized refined type over F[Str]. I’m getting an error trying to match 5 at compile time with both valueOf and constValue.
Is there a way to represent this function using an opaque type? It works with valueOf if I use a case class instead:

case class Sized[N <: Int](f: F[Str]) extends AnyVal

P.S. Is there a way to define the match type SS without running afoul of SIP-56?