I am very sorry to hear fo the camera issues with Snapchat, and can understand the inconvenience. Can you tell me if there is an error message, or in general what you are seeing when the camera stops working? Does it do this with any other apps, or is it just with Snapchat?
You can try this guide for troubleshooting camera behavior: https://www.samsung.com/us/support/troubleshooting/TSG01001329/
Please let me know if this helps, and if you have any information on what you are seeing on your side, thank you.