Several things. Fix primary care. I don't actually have an issue with the PAs - it makes more sense for them to eg see people who need repeat prescriptions or are asking for tests before further investigations are made - eg if someone wants a FIT test before being referred for bowel cancer. You don't really need a GP for that.
I would also introduce insurance for the nice to haves and keep the free NHS for core services - maternity, children's healthcare, A&E and life threatening conditions like cancer. Insurance would eg pay for an elective hip replacement. Everyone would have insurance.
And as a pp said on page one, sort out discharge and ensure that (a) people have help on discharge - some areas are better at this than others, and (b) they are properly supported by the hospital that did their procedure.
Also fix admin so if you phone a hospital someone answers the phone and has the knowledge to answer your question or find out.
Finally stop wasting money. The NHS is well funded - it needs to use that money better.
As for wasted appointments at GPs, given nobody can get an appointment, I fail to see how they are being missed. Are they talking about phone appointments? If so, that does not count. If I am told I will be called sometime between 8 and 6 and happen to be driving when the doctor calls, that is NOT a missed appointment. Only face to face count!