I had to build this package from source because it was no longer available on the ROS 2 package server for Humble.

cd ~/ros2_ws/src
git clone https://github.com/ros2/teleop_twist_keyboard.git
cd ~/ros2_ws
rosdep install --from-paths src --ignore-src -r -y
colcon build --packages-select teleop_twist_keyboard
source install/setup.bash
ros2 run teleop_twist_keyboard teleop_twist_keyboard

I then modified the node script (~/ros2_ws/src/teleop_twist_keyboard/teleop_twist_keyboard.py) to set the default speeds on lines 156 (speed) and 157 (turn) instead of adjusting them using the keyboard on every run, before rebuilding.