Design for Handheld Delay Measuring Device

I'm looking for design ideas for a handheld screen delay measuring device, primarily intended for industrial and consumer measurement of monitors and TV devices.

Key Requirements:
- The device needs to be handheld, making it portable and easy to use in various industrial settings.
- The device should feel comfortable to hold
- The device should be cost effective to manufacture in 100s-1000 quantities. Not 1000+
- It should have a user-friendly interface to ensure ease of use, even for individuals who may not be particularly tech-savvy. This must include buttons for navigation, and a small screen 2" to 2.5" in diagonal viewing area.
- The build quality of the device needs to be durable, capable of withstanding the rigors of industrial use.
- There must be 1 x USB-C connector socket
- There must be 1 x HDMI connector socket
- The HDMI Connector should have space either side in case a 4 x HD-BNC SDI output is required.
- It must be possible to change the HDMI socket for a DP socket.
- A soft touch / silicone material/membrane must be the interface with the surface of the screen under test to avoid scratching of the screen
- There must be a 3-5mm opening for the sensor
- The device should have enough room for a rechargeable battery to fit inside.


Ideal Skills Include:
- Industrial design experience, particularly with handheld devices.
- User interface (UI) design skills.
- Knowledge and experience in creating durable, high-quality designs for industrial equipment.

Please provide your best design ideas for this project.