Webview2 spellcheck suggestions empty for Dutch language

I have a question, about the spell check and how I might be able to get it to work it correctly.
It seems that the behavior of Webview2 does not work the same way it is handled in Edge, and I can't seem to figure out what I am missing in order to get it to work. The suggestions for the Dutch spellcheck do not seem to be shown when right clicking on the word that has a red squiggly line underneath it.

Are there any suggestions on what I could try or need to do to get this to work?

Version
SDK: 1.0.1587.40
Framework: .Net/WPF
OS: Win10

Code to set the language:

var webView2EnvironmentOptions = new CoreWebView2EnvironmentOptions
{
     Language = "nl-NL",
     AdditionalBrowserArguments = $"--remote-debugging-port={Properties.Settings.Default.RemoteDebuggingPort}",
 };

var webview2Environment = await CoreWebView2Environment.CreateAsync(null, null, webView2EnvironmentOptions);
await this.webBrowser.EnsureCoreWebView2Async(webview2Environment);

When I set the language to Dutch(Nederlands), the suggestions for the correct Dutch word is not provided. It only works when I set the selection to All languages or English.

Installed language(s) in Windows

Within Edge
Suggested word in Edge based on form text provided.

It works with the settings: