diff --git a/.github/actions/install-mono/action.yml b/.github/actions/install-mono/action.yml
new file mode 100644
index 000000000..7f0a1f775
--- /dev/null
+++ b/.github/actions/install-mono/action.yml
@@ -0,0 +1,43 @@
+name: 'Install Mono'
+description: 'Install Mono'
+branding:
+  icon: package
+  color: blue
+inputs:
+  arch:
+    description: Architecture to install for
+    required: true
+runs:
+  using: "composite"
+  steps:
+    - name: Install on macOS (x86_64)
+      if: runner.os == 'macOS' && inputs.arch == 'x64'
+      run: |
+        arch -x86_64 /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
+        arch -x86_64 /usr/local/bin/brew install mono
+      shell: sh
+
+    - name: Install on macOS
+      if: runner.os == 'macOS' && inputs.arch != 'x64'
+      run: |
+        brew update
+        brew install mono
+      shell: sh
+
+    - name: Install on Linux
+      if: runner.os == 'Linux'
+      run: |
+        sudo apt update
+        sudo apt install -y mono-runtime-sgen
+      shell: sh
+
+    - name: Install on Windows (x86)
+      if: runner.os == 'Windows' && inputs.arch == 'x86'
+      run: choco install --x86 -y mono
+      shell: sh
+
+    - name: Install on Windows
+      if: runner.os == 'Windows' && inputs.arch != 'x86'
+      run: choco install -y mono
+      shell: sh
+
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 53c0934ae..79399fa78 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -17,36 +17,42 @@ jobs:
       matrix:
         os:
           # Disabled for now, will require some work (#2653)
+          # The main issue is setup-dotnet stubbornly installing for x64 only
           #
           # - category: windows
           #   platform: x86
           #   instance: windows-latest
+          #   suffix:   -windows-x86-none
 
           - category: windows
             platform: x64
             instance: windows-latest
+            suffix:   -windows-x86_64-none
 
           - category: ubuntu
             platform: x64
             instance: ubuntu-22.04
+            suffix:   ""
 
           - category: ubuntu
             platform: arm64
             instance: ubuntu-22.04-arm
+            suffix:   ""
 
           - category: macos
             platform: x64
-            instance: macos-13
+            instance: macos-15
+            suffix:   -macos-x86_64-none
 
-        python: ["3.10", "3.11", "3.12", "3.13"]
+          - category: macos
+            platform: arm64
+            instance: macos-15
+            suffix:   -macos-aarch64-none
 
+        python: ["3.10", "3.11", "3.12", "3.13"]
+    env:
+      NUGET_PACKAGES: ${{ github.workspace }}/.nuget/packages
     steps:
-      - name: Set Environment on macOS
-        uses: maxim-lobanov/setup-xamarin@v1
-        if: ${{ matrix.os.category == 'macos' }}
-        with:
-          mono-version: latest
-
       - name: Checkout code
         uses: actions/checkout@v6
 
@@ -55,33 +61,41 @@ jobs:
         with:
           dotnet-version: '8.0.x'
 
+      - name: Install Mono
+        uses: ./.github/actions/install-mono
+        with:
+          arch: ${{ matrix.os.platform }}
+
+      - name: Setup upterm session
+        uses: owenthereal/action-upterm@v1
+        if: ${{ failure() }}
+        with:
+          ## Shut down the server if unconnected after 5 minutes.
+          limit-access-to-actor: true
+          wait-timeout-minutes: 5
+
       - name: Set up Python ${{ matrix.python }}
         uses: astral-sh/setup-uv@v7
         with:
-          architecture: ${{ matrix.os.platform }}
-          python-version: ${{ matrix.python }}
+          python-version: cpython-${{ matrix.python }}${{ matrix.os.suffix }}
           cache-python: true
           activate-environment: true
           enable-cache: true
 
+      - run: dotnet restore
+
       - name: Synchronize the virtual environment
         run: uv sync --managed-python
 
-      - name: Show pyvenv.cfg
-        run: cat .venv/pyvenv.cfg
-
       - name: Embedding tests (Mono/.NET Framework)
         run: dotnet test --runtime any-${{ matrix.os.platform }} --framework net472 --logger "console;verbosity=detailed" src/embed_tests/
-        if: always()
         env:
           MONO_THREADS_SUSPEND: preemptive # https://github.com/mono/mono/issues/21466
 
       - name: Embedding tests (.NET Core)
         run: dotnet test --runtime any-${{ matrix.os.platform }} --framework net8.0 --logger "console;verbosity=detailed" src/embed_tests/
-        if: always()
 
       - name: Python Tests (Mono)
-        if: ${{ matrix.os.category != 'windows' }}
         run: pytest --runtime mono
 
       - name: Python Tests (.NET Core)