I can only say about AQA and Edexcel - as that's what I specialise in. I've written software to analyse topic-wise questions from both these boards. And then done further analysis on sub-topics. I generated the probabilities of questions from all sub-topics in both boards. I did not use AI.
Many questions are straight forward in both boards. One of them definitely has a more challenging Foundation paper. One also has so, so many 1-markers which occasionally take a long time to read and analyse.
For the Higher paper, one board has more questions on high grade topics but those are still easy to revise for. The other board has a more even spread, but boy, can the wording be tricky. Sometimes it seems more like an English language paper!
It may come as a surprise that entire sub-topics are skipped in one board, but quite common in another.
To summarise, prep for the exam board is key in GCSE Maths! The student also needs to prepare for high probability sub-topics in the exam board. This smart prep ensures that key marks are not lost and could take one the next grade up.
Please look at my reviews to see how my students have benefitted from my research and experience. And get in touch if you need any help. You can find more about me here.