The choice between AQA and Edexcel doesn't impact how universities view your application. Both exam boards are widely recognized and respected. The key is to choose the one that best aligns with your learning style.
AQA often focuses on essay-based questions while Edexcel tends to include a mix of question types, including multiple-choice, short answers, and calculations, along with essays.
If you prefer essay, I would go with AQA, othrewise edexcel. One thing you can do is take one subject like English and write down the exam same essay then put it on Tilf website and compare the grade you get from AQA vs Edexcel so you see which is already more aligned with your style.