[Problem/Bug]: WebView2 deadlocks and crashes when sending large messages on ARM64 Windows with x64 target

What happened?

Description:
When running a WebView2-based application built with C# targeting x64 on an ARM64 Windows machine, attempting to send large messages to the WebView2 control leads to deadlocks and eventual crashes of the entire application. This issue occurs in the following scenarios:

1. Returning large data from a [ComVisible] method on a bridge between C# and JavaScript.
2. Posting large JSON payloads to the WebView2 control using CoreWebView2.PostWebMessageAsJson.
3. Sending large strings to the WebView2 control using CoreWebView2.PostWebMessageAsString.

The application becomes unresponsive and eventually crashes, indicating a fundamental issue with the translation layer for WebView2 when running x64 applications on ARM64 Windows.

Expected behavior:
The application should be able to send and receive large messages without any deadlocks or crashes, regardless of the target platform (x64) and the underlying architecture (ARM64).

Actual behavior:
The application deadlocks when attempting to send large messages to the WebView2 control and eventually crashes, making it impossible to use WebView2 reliably in x64 applications running on ARM64 Windows.

Additional context:
This issue is critical for developers targeting x64 applications that use WebView2 and need to support ARM64 Windows devices, especially since Steam only supports the x64 platform. The deadlocks and crashes make it impossible to use WebView2 reliably in such scenarios, severely limiting the usability of the control on ARM64 Windows machines.

Importance

Blocking. My app's basic functions are not working due to this issue.

Runtime Channel

Stable release (WebView2 Runtime), Prerelease (Edge Canary/Dev/Beta)

Runtime Version

1.0.2526-prerelease

SDK Version

1.0.2526-prerelease

Framework

Win32 (.NET 9) (I am manually creating and managing my window without winforms or WPF, but the official example apps crash too.)

Operating System

Windows 11

OS Version

No response

Repro steps

1. Set up a Windows 11 ARM64 virtual machine running on macOS with an M1 processor.
2. Create a C# application that uses WebView2 and targets the x64 platform (as it is the only platform supported by Steam).
3. Implement a scenario where large messages are sent to the WebView2 control, such as:

• Returning large data from a [ComVisible] method on a bridge between C# and JavaScript.
• Posting large JSON payloads using CoreWebView2.PostWebMessageAsJson.
• Sending large strings using CoreWebView2.PostWebMessageAsString.

4. Run the application on the ARM64 Windows virtual machine.

Repros in Edge Browser

No, issue does not reproduce in the corresponding Edge version

Regression

Don't know

Last working version (if regression)

No response