What level thesis? Masters, doctorate? What sort of skill set do you have?
Last year about this time, I was tutoring a woman in Scotland, working on her Masters, who was building a front-end survey form designer. Ended up being a complete end-to-end solution, with survey creation, the ability to track surveys, multiple retakes, survey heatmaps, the whole thing.
Ended up evolving into an exercise in building an authenticated RESTful API, database structures, handling collections on the front end, and (as she wanted the entire thing to be library-agnostic) built from scratch. We custom-built a solution for MVC, we created a front-end store along the lines of Redux (without a full react library), just a lot of code.
Not saying you have to do something that elaborate, but what are your particular skillsets? What are your interests? Start with what you know and what you like, it will make much more sense.