Wa `alaykum as-Salamu wa Rahmatullahi wa Barakatuh.

 

There is nothing unlawful about your work as an engineer or maintenance work in this field. It is not different from any other work. You are only providing a lawful service; you are not responsible for what people do with the system you are maintaining. According to the rules of jurisprudence, “We are not liable for that which is out of our hands or sights.”

 

In the case of doubt in your mind, you should purify your income through voluntary charities and lots of Istighfar.

Almighty Allah knows best.