I have to take a deeper look at the LDA model method first so I can't say too much about this right now. But one key focus in this project was explicitly NOT to use methods that need "more processing power" or a backend-service, e.g. and instead use a seemingly "trivial" method like looking for occurencies matched with a keyword-list. But maybe LDA can also be implemented in a frontend package? I will take a look, thanks for the hint. And it would also be helpful for me if you can give me some info about the other "similarly established methods". Thank you!
The keyword you are looking for is "topic modeling". For SOTA (state of the art) methods, look on arxiv.