From Arduino to an Industrial design
At the firmware side, Arduino approach can be used for 'serious' projects whenever you know what you are doing. The problem regarded to Arduino is that their ready-and-easy-to-use libraries allow almost everything work with few lines of code, but it often occurs at the limit of opperability. Many people don't know good practices, such as replace delays by interrupt driven time slot, etc...Keep in mind that the Arduino IDE just provide a kind of "front-end" interface to a compilation which is indeed made in C/C++ language inside. Me, I always programmed in C, but more recently I've migrated to this platform for some specific cores with no issues.

At the hardware side, in other hand although Arduino is nice in the sence that too often you can stack-up shields with no worry in regard to pinouts, in other hand it provides a poor quality path for signals in termos of EMI susceptibility with the aerial arrangment as well as the spread characteristic routing on PCB, therefore you should consider making your own layout.