A lot comes down to what GCSEs and A levels are actually intended to do.
Basically they're a sieving system.
Who is suited to A levels, who is suited to academic university degrees, who is suited to university degrees pitched at a particular level.
Not all children are suited to everything.
DH and I were very academic, DD is the complete opposite. She would be utterly miserable doing A levels - regardless of her CAT scores. She will be blissfully happy doing a L3 Extended BTEC which is a great fit, and it doesn't limit her university choices in anyway.
If a child is only really capable of getting a 5 in Maths, then they really shouldn't be considering Maths A level or a Maths degree. It's not going to be a happy experience for anyone.
Maybe better if parents focused more on their own child and how they fit within the system we have.
My child having extra time and a laptop doesn't affect your child's results in any way whatsoever.
If you feel your child struggles in a way that is seriously impacting their getting an exam grade that is in line with their ability, then pick up the phone to school and discuss it.
DD's dyslexia is so severe that it is blatantly obvious to everyone, so everything from Ed Psych to Access Arrangements was just automatically sorted. But, I still contacted school to discuss whether it was better to enable spell-check and editing in exchange for an automatic deduction of all SPaG marks in all exams (20% in English Lang, 5-6% in most others) or hope she might manage to scrape a few marks that made it worthwhile. I worried her syntax will make examiners think she's stupid and they won't give benefit of the doubt etc.
And anyone whinging about access arrangements at school being unfair is going to explode when they see what you get later on. We have colleges and universities falling over themselves to explain how much support and tech they will be putting in place. After the very real stress over the last few years it's amazing.