Turns out this whole time I wasn't even using yarn@3

.github/workflows/deploy.yml

@@ -21,23 +21,12 @@ jobs:
       - name: Checkout your repository using git
         uses: actions/checkout@v3
 
-      - name: Setup Node.js
-        uses: actions/setup-node@v3
-        with:
-          node-version: 18
-
-      - name: Install Yarn 3.3.1
-        run: npm install -g [email protected]
-
-      - name: Check Yarn Version
-        run: yarn --version
-
       - name: Install, build, and upload your site
         uses: withastro/action@v1
         with:
           path: blog # The root location of your Astro project inside the repository. (optional)
-          # node-version: 19 # The specific version of Node that should be used to build your site. Defaults to 18. (optional)
-          # package-manager: yarn@3.3.1 # The Node package manager that should be used to install dependencies and build your site. Automatically detected based on your lockfile. (optional)
+          node-version: 18 # The specific version of Node that should be used to build your site. Defaults to 18. (optional)
+          package-manager: yarn@1.22.19 # The Node package manager that should be used to install dependencies and build your site. Automatically detected based on your lockfile. (optional)
 
   deploy:
     needs: build

blog/package.json

@@ -63,5 +63,5 @@
     "three": "^0.154.0",
     "threlte": "^3.13.1"
   },
-  "packageManager": "yarn@3.3.1"
+  "packageManager": "yarn@1.22.19"
 }