authorizationStatusForType().md

Check the authorization status for sharing (writing) the specified data type.

Status will be one of "NotDetermined", "SharingDenied", "SharingAuthorized".

try {
const status = await AppleHealthKit.authorizationStatusForType("StepCount")
if (status) {
  console.log("status is", status)
}
} catch (error) {
  console.warn(error)
}

There is no way to check authorization status for read permission, see this.