Unable to load controllers for URDF model in Gazebo and ROS Noetic

Question

I'm trying to use some rather old ROS packages to control a simple simulation of a Robotis OP1 robot, using the darwin_description and darwin_control packages, but I'm facing a weird issue, whenever I use the bundled launch file in darwin_control I get the following messages/warning:

[INFO] [1729969219.133353, 0.000000]: Controller Spawner: Waiting for service controller_manager/load_controller
[WARN] [1729969249.437919, 97.394000]: Controller Spawner couldn't find the expected controller_manager ROS interface.

with the spawner node eventually terminating with no controller loaded. Prior to launching controllers, I'm successfully spawning the URDF model in Gazebo in a rather straightforward manner:

rosparam load src/darwin_description/urdf/darwin.urdf /robot_description

roslaunch gazebo_ros empty_world.launch

rosrun gazebo_ros spawn_model -param /darwin/robot_description -urdf -model darwin

If relevant, I'm using a virtual machine w/ Ubuntu and ROS installation; I've read that controller_manager initialization is resource-dependent and may hang on virtual systems. I am also sure these packages somehow worked in ROS1 Melodic, so I wonder if the issue is somehow caused by some update to ros-noetic-controller-manager; in any case, I'm not sure what is missing here.