diff --git a/lib/dl_api_lib/dl_api_lib/app/control_api/resources/connections.py b/lib/dl_api_lib/dl_api_lib/app/control_api/resources/connections.py
index e48c79fef..201e41d32 100644
--- a/lib/dl_api_lib/dl_api_lib/app/control_api/resources/connections.py
+++ b/lib/dl_api_lib/dl_api_lib/app/control_api/resources/connections.py
@@ -67,10 +67,11 @@ def _handle_conn_test_exc(exception: Exception) -> NoReturn:
 @ns.route("/test_connection_params")
 class ConnectionParamsTester(BIResource):
     @schematic_request(ns=ns)
-    def post(self):  # type: ignore  # TODO: fix
+    def post(self) -> None:
         service_registry = self.get_service_registry()
         schema = GenericConnectionSchema(context=self.get_schema_ctx(schema_operations_mode=CreateMode.test))
-        body_json = dict(request.json)  # type: ignore  # 2024-01-24 # TODO: Argument 1 to "dict" has incompatible type "Any | None"; expected "SupportsKeysAndGetItem[Any, Any]"  [arg-type]
+        body_json = request.get_json()
+        assert isinstance(body_json, dict)
         body_json["name"] = "mocked_name"  # FIXME: BI-4639
         try:
             conn: ConnectionBase = schema.load(body_json)
@@ -93,7 +94,7 @@ def post(self):  # type: ignore  # TODO: fix
 @ns.route("/test_connection/<connection_id>")
 class ConnectionTester(BIResource):
     @schematic_request(ns=ns)
-    def post(self, connection_id):  # type: ignore  # TODO: fix
+    def post(self, connection_id: str) -> None:
         usm = self.get_us_manager()
         service_registry = self.get_service_registry()
         conn = usm.get_by_id(connection_id, expected_type=ConnectionBase)
@@ -101,7 +102,8 @@ def post(self, connection_id):  # type: ignore  # TODO: fix
         assert isinstance(conn_orig, ConnectionBase)  # for typing
         need_permission_on_entry(conn, USPermissionKind.read)
 
-        body_json = dict(request.json)  # type: ignore  # 2024-01-24 # TODO: Argument 1 to "dict" has incompatible type "Any | None"; expected "SupportsKeysAndGetItem[Any, Any]"  [arg-type]
+        body_json = request.get_json()
+        assert isinstance(body_json, dict)
 
         has_changes = len(body_json.keys()) > 0
         if has_changes:
@@ -131,7 +133,7 @@ def post(self, connection_id):  # type: ignore  # TODO: fix
 class ConnectionsImportList(BIResource):
     @put_to_request_context(endpoint_code="ConnectionImport")
     @schematic_request(ns=ns)
-    def post(self):  # type: ignore  # TODO: fix
+    def post(self) -> None:
         us_manager = self.get_us_manager()
         notifications = []
 
@@ -173,7 +175,7 @@ def post(self):  # type: ignore  # TODO: fix
 class ConnectionsList(BIResource):
     @put_to_request_context(endpoint_code="ConnectionCreate")
     @schematic_request(ns=ns)
-    def post(self):  # type: ignore  # TODO: fix
+    def post(self) -> None:
         us_manager = self.get_us_manager()
 
         conn_availability = self.get_service_registry().get_connector_availability()
@@ -229,10 +231,10 @@ def delete(self, connection_id: str) -> None:
 
     @put_to_request_context(endpoint_code="ConnectionUpdate")
     @schematic_request(ns=ns)
-    def put(self, connection_id):  # type: ignore  # TODO: fix
+    def put(self, connection_id: str) -> None:
         us_manager = self.get_us_manager()
 
-        with us_manager.get_locked_entry_cm(ConnectionBase, connection_id) as conn:  # type: ignore  # TODO: fix
+        with us_manager.get_locked_entry_cm(ConnectionBase, connection_id) as conn:
             need_permission_on_entry(conn, USPermissionKind.edit)
             conn_orig = us_manager.clone_entry_instance(conn)
             assert isinstance(conn_orig, ConnectionBase)
@@ -242,7 +244,9 @@ def put(self, connection_id):  # type: ignore  # TODO: fix
             schema = schema_cls(context=schema_ctx)
 
             try:
-                changes = schema.load(request.json)  # type: ignore  # 2024-01-24 # TODO: Argument 1 to "load" of "Schema" has incompatible type "Any | None"; expected "Mapping[str, Any] | Iterable[Mapping[str, Any]]"  [arg-type]
+                body_json = request.get_json()
+                assert isinstance(body_json, dict)
+                changes = schema.load(body_json)
                 schema.update_object(conn, changes)
             except MValidationError as e:
                 return e.messages, 400
@@ -319,7 +323,7 @@ class ConnectionInfoSources(BIResource):
         query=ConnectionSourcesQuerySchema(),
         responses={200: ("Success", ConnectionSourceTemplatesResponseSchema())},
     )
-    def get(self, connection_id, query):  # type: ignore  # TODO: fix
+    def get(self, connection_id: str, query: dict) -> dict:
         connection = self.get_us_manager().get_by_id(connection_id, expected_type=ConnectionBase)
 
         service_registry = self.get_service_registry()
@@ -357,7 +361,7 @@ class ConnectionInfoSourceSchema(BIResource):
         body=ConnectionInfoSourceSchemaQuerySchema(),
         responses={200: ("Success", ConnectionInfoSourceSchemaResponseSchema())},
     )
-    def post(self, connection_id: str, body: dict):  # type: ignore  # TODO: fix
+    def post(self, connection_id: str, body: dict) -> dict:
         connection = self.get_us_manager().get_by_id(connection_id, expected_type=ConnectionBase)
         sr = self.get_service_registry()