Cannot load WebView2Loader.dll in Excel VSTO Add-In

Description
I'm building a VSTO Add-In using Visual Studio 2019 on Windows 10.
After adding the ribbon, windows form and the WebView2 user control I get an error message saying that said DLL cannot be found.

Version
SDK: 1.0.1189-prerelease
Runtime: Evergreen 99.0.1150.55
Framework: WinForms
OS: Win10 21H2 Build 19044.1586

Repro Steps

• open Visual Studio 2019
• create new project
• search for VSTO
• select Excel-VSTP-Add-In
• name it excel-vsto-webview
• add a Ribbon (XML) via insert new element
• add custom ribbon code (XML) to show button near File->Save As
• initialize ribbon in addin class
• OK: pressing F5, creating empty workbook, clicking File, Save,
  My custom task, My Button results in a message box popup
• add a Windows Form via insert menu
• show form instead of message box in ribbon code (button click)
• OK: pressing F5, creating empty workbook, clicking File, Save,
  My custom task, My Button results in an empty Form window popping up
• add WebView2 NuGet package via package manager, version 1.0.1189-prerelease
• drag WebView2 Windows Forms control into Form1 using the designer
• OK: pressing F5, creating empty workbook, clicking File, Save,
  My custom task, My Button results in an empty Form window popping up
• adding webview2 init code from @cgeier https://github.com/MicrosoftEdge/WebView2Feedback/issues/187
• NOK: pressing F5, creating empty workbook, clicking File, Save,
  My custom task, My Button results in an empty Form window popping up
  plus error message, telling me it cant find a dll called WebView2Loader.dll

Screenshots

Additional context
Repository containing exactly what is mentioned in repro steps: https://github.com/FROGGS/excel-vsto-webview