Idea as to which textbook is better? URGENTWatch
But Collins is really good imo.
For Edexcel, I did completely new specification, no past papers but only a few practice papers, which were quite useless imo.
For CIE, I think they’re gonna make 2 papers into 4 papers. My advice is that you look through a few question papers, checking whether there’s topics you haven’t learned and do the ones you have. I think the question style of CIE shouldn’t change as the exam board itself is known to be a difficult one. So, I don’t think you have a lot of options but the textbook questions and past papers (despite not being in the same format) should be adequate.