How can I overcome the struggle of Waswas and OCD while making Dua, as I sometimes unintentionally say things I don't want to happen or add "Insha Allah" to something undesired?
First step in tackling Waswas and OCD is to know its origin which is Shaitan who wants to harm us in every way. We need to be aware and very careful against Shaitan and Satanic thiuts. We need to repeat Isteghfaar and Salawaat and La Hawla Wala Qowwata Illa Billah. Repeating Laa Ilaha Illallah is also very useful in tackling Satanic thoughts.
Wassalam.