Maybe this helps?

.readthedocs.yaml

@@ -9,10 +9,10 @@ conda:
   environment: doc/environment.yml
 
 # Set the version of Python and other tools you might need
-build:
-  os: ubuntu-20.04
-  tools:
-    python: "3.10"
+# build:
+#   os: ubuntu-20.04
+  # tools:
+    # python: "3.10"
     # You can also specify other tool versions:
     # nodejs: "16"
     # rust: "1.55"
@@ -30,3 +30,10 @@ sphinx:
 #python:
 #   install:
 #   - requirements: doc/requirements.txt
+
+# This part is necessary otherwise the project is not built
+python:
+   version: 3.10
+   install:
+      - method: pip
+        path: .
\ No newline at end of file