TextResource.csproj

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net7.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <EmbeddedResource Include="Resources\MyResources.restext">
      <StronglyTypedLanguage>C#</StronglyTypedLanguage>
      <StronglyTypedFileName>Resources\MyResources.Designer.cs</StronglyTypedFileName>
      <StronglyTypedNamespace>$(RootNamespace).Resources</StronglyTypedNamespace>
      <StronglyTypedClassName>MyResources</StronglyTypedClassName>
    </EmbeddedResource>
    <EmbeddedResource Include="Resources\MyResources.ja-jp.restext"/>
  </ItemGroup>

</Project>