Yes, you can use an ultrasound module with an Arduino to measure the depth of the object that the laser is pointing at. This can be done by sending out a pulse of ultrasound waves and measuring the time it takes for the waves to bounce back to the module. From this time, you can calculate the distance to the object.
Additionally, incorporating a variable focal point lens with the laser can allow you to adjust the focus of the laser beam, making it more in-focus at various distances. This can improve the accuracy and precision of your measurement system. However, it's important to note that the variable focal point lens will add complexity to your system and may also increase the cost. Before implementing this solution, it is recommended to carefully consider the requirements and goals of your project to ensure that this added complexity is justified.