fix(js): Clarify scope setting docs (#13635)

Closes
https://linear.app/getsentry/issue/FE-405/user-feedback-elaborate-on-current-scope-usage

---------

Co-authored-by: Alex Krawiec <[email protected]>
Co-authored-by: Andrei <[email protected]>

Author: 3 people

docs/platforms/javascript/common/enriching-events/scopes/index.mdx

@@ -106,34 +106,33 @@ Sentry.captureException(new Error("my error"));
 
 ## Configuring the Scope
 
-There are two main ways to interact with the scope. You can access the current scope via `Sentry.getCurrentScope()` and use setters on the resulting scope, or you can use global methods like `Sentry.setTag()` directly, which will set on the respective scope under the hood (which will be the isolation scope).
+In most cases, you should use top-level methods like `Sentry.setTag()` directly, which will set the data on the isolation scope, ensuring it is applied to all events related to the current request/process.
 
-You'll first need to import the SDK, as usual:
+If you want to apply data to a more narrow scope, you can use `withScope` to create a new scope that is only active for a specific part of your code. `withScope` receives the scope as a callback argument, which you can use to set data on the scope.
 
 <PlatformContent includePath="enriching-events/import" />
 
 You can, for instance, add custom tags or inform Sentry about the currently authenticated user.
 
 ```javascript
-/// Usually, you don't want to write on the current scope, so use with care!
-const scope = Sentry.getCurrentScope();
-scope.setTag("my-tag", "my value");
-scope.setUser({
-  id: 42,
-  email: "[email protected]",
-});
-
-// Or use the global methods (which will set data on the isolation scope):
 Sentry.setTag("my-tag", "my value");
 Sentry.setUser({
   id: 42,
   email: "[email protected]",
 });
+
+// Alternatively, you can use `withScope` as documented below.
 ```
 
 To learn what useful information can be associated with scopes see
 [context](../context/), [tags](../tags), [users](../identify-user) and [breadcrumbs](../breadcrumbs/).
 
+We recommend you avoid using `getCurrentScope()` and setting data on it, as the current scope can have an unreliable lifetime. Instead:
+
+* If you want to apply data to the current request/process (in Node) or the current page view (in browser), use the top-level methods, e.g. `Sentry.setTag()`.
+* If you want to apply data to all events, no matter where they are captured, use methods on the global scope, e.g. `getGlobalScope().setTag()`
+* If you want to apply data to a more narrow scope, use `withScope` to create a new scope that is only active for a specific part of your code.
+
 ## Using `withScope`
 
 In the following example we use <PlatformIdentifier name="with-scope" /> to attach a `level` and a `tag` to only one specific error: