Can you give some actual evidence? Studies have shown it to be one of the most efficient health services in the world. At individual trust level it does not have enough management or supporting infrastructure, they are managed on a shoestring, a private company that had an equivalent turnover to an average Trust would employ an awful lot more people to manage it. There might be an argument to say there are some people employed in central government for NHSE who serve little useful purpose but that's not what I believe you're talking about.
The NHS does not have enough resources on the front line, which is the biggest hole. The bigger the hole, the more negligence claims there are as well (13.6 billion pounds in 2021). Now, that can be solved by throwing more money at it. I'm not saying it doesn't need more funding. It would however, also make more sense if the money was spread out better from where it is being wasted across the entire NHS and put into more useful places. That's the point I am making, and I can't take anyone seriously who is genuinely saying that the NHS isn't wasting money.
If you want, in your words, actual evidence, then you can find it in a whole heap of places. Start here, by looking at the spending reports for the NHS:
NHS England » What we spend and how we spend it
A quick google 'where does the NHS waste money' will show you article after article of further breakdowns, and might help crunch the data a bit easier. That said, if you don't want to acknowledge personal accounts from people that have worked in the NHS or in its supply chain (that includes myself, members of my family, and other people that have posted on this board), then I'm not sure you'll be prepared to listen to any other points of view whatsoever. There is such a waste of money in useless job roles, middle management positions, contracted agency staff, stock procurement, dodgy contracts, and overpriced equipment.
I don't agree with underfunding of our health service, or the emergency services in general, neither the shit pay that these people get paid for doing the work they do. It's a disgrace in that sense. If we are that fucked though (we are), then there needs to be a much smarter approach to how money is spent across the entire NHS. The budget for 2022/23 is about 180 billion, there's no question a chunk of that could be better used.