What are some common design patterns used in RPA?

I recently accepted my first SWE role as a .NET(Mostly C#) automation developer. The automations I develop run against old mainframe systems and my bots basically have to navigate the screens of the mainframe GUI to gather data for making decisions and then go to other screens to make changes according to business rules. It really locks the bot into doing things the same way a user of the mainframe would. The senior SWE I work with makes use of a large static class with a ton of methods to do most of the work and a few other classes that really only work as containers for data(No methods of their own) for the static class to play with. I imagine there is a better way to make use of OOP design patterns, but all my searches for "RPA design patterns" result in links for UIpath or some similar tool. Are there any design patterns you would suggest for RPA against the mainframe system I described, or maybe RPA in general?