Single Build with Multiple Artifacts

I'm a little confused on the Azure Pipeline steps. My solutions has many projects and one UI project that contains both an ASP.Net-Core WebApi/MVC with Angular.

the Build Solution builds similar to the

steps:
- task: VSBuild@1
  displayName: 'Build solution'
  inputs:
    solution: '$(Parameters.solution)'
    msbuildArgs: '/p:DeployOnBuild=true 
      /p:WebPublishMethod=Package 
      /p:PackageAsSingleFile=true 
      /p:SkipInvalidConfigurations=true 
      /p:PackageLocation="$(build.artifactstagingdirectory)\\"'
    platform: '$(BuildPlatform)'
    configuration: '$(BuildConfiguration)'

The default Publish Artifact is:

steps:
- task: PublishBuildArtifacts@1
  displayName: 'Publish Artifact: drop'
  inputs:
    PathtoPublish: '$(build.artifactstagingdirectory)'
  condition: succeededOrFailed()

I'd like to do something with 2 artifacts (this doesn't work):

steps:
- task: PublishBuildArtifacts@1
  displayName: 'Publish Artifact: webapi'
  inputs:
    PathtoPublish: '$(build.artifactstagingdirectory)\\MVCProject\bin\$(BuildConfiguration)\netcorapp2.2'
    ArtifactName: webapi
  condition: succeededOrFailed()

steps:
- task: PublishBuildArtifacts@1
  displayName: 'Publish Artifact: angular'
  inputs:
    PathtoPublish: '$(build.artifactstagingdirectory)\\MVCProject\clientapp\dist'
    ArtifactName: angular
  condition: succeededOrFailed()

What am I missing / What the right/better way to do this.
(moving angular out of the project does not solve this problem, and we aren't ready for that yet)

Here is my YAML for multiple artifacts from a single build.

pool:
  name: Hosted Windows 2019 with VS2019
  demands:
  - msbuild
  - visualstudio
  - vstest
  - npm

steps:
- task: NuGetToolInstaller@0
  displayName: 'Use NuGet 4.4.1'
  inputs:
    versionSpec: 4.4.1

- task: NuGetCommand@2
  displayName: 'NuGet restore'
  inputs:
    restoreSolution: '$(Parameters.solution)'

- task: VSBuild@1
  displayName: 'Build solution WebApi'
  inputs:
    solution: '$(Parameters.solution)'
    msbuildArgs: '/p:DeployOnBuild=true /p:WebPublishMethod=Package /p:PackageAsSingleFile=true /p:SkipInvalidConfigurations=true /p:PackageLocation="$(build.artifactstagingdirectory)\\"'
    platform: '$(BuildPlatform)'
    configuration: '$(BuildConfiguration)'
    msbuildArchitecture: x64

- task: PublishBuildArtifacts@1
  displayName: 'Publish Artifact: WebApi'
  inputs:
    PathtoPublish: '$(build.artifactstagingdirectory)'
    ArtifactName: 'dotnet-webapi'
  condition: succeededOrFailed()

- task: DeleteFiles@1
  displayName: 'Delete build.artifactstagingdirectory for Angular'
  inputs:
    SourceFolder: '$(build.artifactstagingdirectory)'
    Contents: '**'

- task: Npm@1
  displayName: 'npm install'
  inputs:
    workingDir: project/ClientApp
    verbose: false

- task: Npm@1
  displayName: 'npm run prod-build'
  inputs:
    command: custom
    workingDir: project/ClientApp
    verbose: false
    customCommand: 'run prod-build'

- task: Npm@1
  displayName: 'npm run dev-build'
  inputs:
    command: custom
    workingDir: project/ClientApp
    verbose: false
    customCommand: 'run prod-dev'
  enabled: false

- task: CopyFiles@2
  displayName: 'Copy Angular/Dist to build.artifactstagingdirectory'
  inputs:
    SourceFolder: project/ClientApp/dist/ClientApp
    Contents: |
     **
     !config.json
    TargetFolder: '$(build.artifactstagingdirectory)'

- task: PublishBuildArtifacts@1
  displayName: 'Publish Artifact: Angular'
  inputs:
    ArtifactName: angular

StackExchange DevOps Q#9156, answer score: 10