JavaScript: Difference Between getPrototypeOf vs __proto__ Property

What is the difference between getPrototypeOf vs .__proto__ Property

• __proto__ may fail when a object in its parent chain has a string key "__proto__".
• __proto__ fails when object does not have a parent.
• __proto__ is not supported in Deno, TypeScript.
• __proto__ is not standard JavaScript, but is mentioned in appendix of JavaScript spec.
• __proto__ works via inheritance over prototype object Object.prototype.__proto__
• Reflect.getPrototypeOf and Reflect.setPrototypeOf always work, and are in JavaScript spec.