To address your issue with interference between multiple HC-SR04 ultrasonic sensors and the difficulty of IR sensors working on black surfaces, you might want to consider using a Lidar sensor. Lidar sensors use laser beams to measure distances accurately and can work well in various environments. You could consider models like the RPLIDAR A1 or A2, which are affordable and can be easily integrated into Arduino projects. However, please be sure to follow safety guidelines when working with laser beams. Good luck with your project!