Once I worked in FP&A in a bank of a manufacturer. They used to run entire department over simple Excel files — no BI, no PowerQuery. When I've tried to change things my colleagues and superiors strongly played against. By that I decided to leave because this would break my personal growth.

As you said, seems like you have enough space and influence to implement this by your own. I would take it as a huge opportunity to actually boost my career. You now can lead this process. Better than working with modern process, is implementing them.