diff --git a/lib/internal/webstreams/queuingstrategies.js b/lib/internal/webstreams/queuingstrategies.js
index df114a44cc8adc..8fbc87642ebc0c 100644
--- a/lib/internal/webstreams/queuingstrategies.js
+++ b/lib/internal/webstreams/queuingstrategies.js
@@ -8,7 +8,6 @@ const {
 
 const {
   codes: {
-    ERR_INVALID_THIS,
     ERR_MISSING_OPTION,
   },
 } = require('internal/errors');
@@ -20,21 +19,12 @@ const {
 
 const {
   customInspect,
-  isBrandCheck,
-  kType,
-  kState,
 } = require('internal/webstreams/util');
 
 const {
   validateObject,
 } = require('internal/validators');
 
-const isByteLengthQueuingStrategy =
-  isBrandCheck('ByteLengthQueuingStrategy');
-
-const isCountQueuingStrategy =
-  isBrandCheck('CountQueuingStrategy');
-
 /**
  * @callback QueuingStrategySize
  * @param {any} chunk
@@ -68,7 +58,8 @@ const getNonWritablePropertyDescriptor = (value) => {
  * @type {QueuingStrategy}
  */
 class ByteLengthQueuingStrategy {
-  [kType] = 'ByteLengthQueuingStrategy';
+  #state;
+  #byteSizeFunction = byteSizeFunction;
 
   /**
    * @param {{
@@ -82,7 +73,7 @@ class ByteLengthQueuingStrategy {
 
     // The highWaterMark value is not checked until the strategy
     // is actually used, per the spec.
-    this[kState] = {
+    this.#state = {
       highWaterMark: +init.highWaterMark,
     };
   }
@@ -92,22 +83,18 @@ class ByteLengthQueuingStrategy {
    * @type {number}
    */
   get highWaterMark() {
-    if (!isByteLengthQueuingStrategy(this))
-      throw new ERR_INVALID_THIS('ByteLengthQueuingStrategy');
-    return this[kState].highWaterMark;
+    return this.#state.highWaterMark;
   }
 
   /**
    * @type {QueuingStrategySize}
    */
   get size() {
-    if (!isByteLengthQueuingStrategy(this))
-      throw new ERR_INVALID_THIS('ByteLengthQueuingStrategy');
-    return byteSizeFunction;
+    return this.#byteSizeFunction;
   }
 
   [kInspect](depth, options) {
-    return customInspect(depth, options, this[kType], {
+    return customInspect(depth, options, 'ByteLengthQueuingStrategy', {
       highWaterMark: this.highWaterMark,
     });
   }
@@ -123,7 +110,8 @@ ObjectDefineProperties(ByteLengthQueuingStrategy.prototype, {
  * @type {QueuingStrategy}
  */
 class CountQueuingStrategy {
-  [kType] = 'CountQueuingStrategy';
+  #state;
+  #countSizeFunction = countSizeFunction;
 
   /**
    * @param {{
@@ -137,7 +125,7 @@ class CountQueuingStrategy {
 
     // The highWaterMark value is not checked until the strategy
     // is actually used, per the spec.
-    this[kState] = {
+    this.#state = {
       highWaterMark: +init.highWaterMark,
     };
   }
@@ -147,22 +135,18 @@ class CountQueuingStrategy {
    * @type {number}
    */
   get highWaterMark() {
-    if (!isCountQueuingStrategy(this))
-      throw new ERR_INVALID_THIS('CountQueuingStrategy');
-    return this[kState].highWaterMark;
+    return this.#state.highWaterMark;
   }
 
   /**
    * @type {QueuingStrategySize}
    */
   get size() {
-    if (!isCountQueuingStrategy(this))
-      throw new ERR_INVALID_THIS('CountQueuingStrategy');
-    return countSizeFunction;
+    return this.#countSizeFunction;
   }
 
   [kInspect](depth, options) {
-    return customInspect(depth, options, this[kType], {
+    return customInspect(depth, options, 'CountQueuingStrategy', {
       highWaterMark: this.highWaterMark,
     });
   }
diff --git a/test/parallel/test-whatwg-webstreams-coverage.js b/test/parallel/test-whatwg-webstreams-coverage.js
index f0036723b05977..4d0ffe818f43f8 100644
--- a/test/parallel/test-whatwg-webstreams-coverage.js
+++ b/test/parallel/test-whatwg-webstreams-coverage.js
@@ -26,25 +26,29 @@ assert(isPromisePending(new Promise(() => {})));
 assert.throws(() => {
   Reflect.get(ByteLengthQueuingStrategy.prototype, 'highWaterMark', {});
 }, {
-  code: 'ERR_INVALID_THIS'
+  name: 'TypeError',
+  message: /Cannot read private member/,
 });
 
 assert.throws(() => {
   Reflect.get(ByteLengthQueuingStrategy.prototype, 'size', {});
 }, {
-  code: 'ERR_INVALID_THIS'
+  name: 'TypeError',
+  message: /Cannot read private member/,
 });
 
 assert.throws(() => {
   Reflect.get(CountQueuingStrategy.prototype, 'highWaterMark', {});
 }, {
-  code: 'ERR_INVALID_THIS'
+  name: 'TypeError',
+  message: /Cannot read private member/,
 });
 
 assert.throws(() => {
   Reflect.get(CountQueuingStrategy.prototype, 'size', {});
 }, {
-  code: 'ERR_INVALID_THIS'
+  name: 'TypeError',
+  message: /Cannot read private member/,
 });
 
 // Custom Inspect Works