Have a nearly 16 year old now and I cannot remember any awful parties when she was young, hosting or as a guest. The main thing is they are entertained, fed (proper party food- this is what children want, especially those raised on lentils and yaks milk) and a party bag. 90 mins to 2 hours, loads of money spent on Instagram worthy decorations is totally wasted on the children.
What I remember is you have to keep them entertained ALL THE TIME, an entertainer or soft play may seem expensive but they usually know what they are doing. Pass the parcel is a big thing, however if a whole class party maybe consider having 2 rounds if you insist on every child opening a layer (experience😁). Kids still love traditional party games, however if you are running a party yourself you will realise you sound like a teacher trying to keep control. If adults stay, access to coffee/tea is fine, no need for alcohol- no expectation of being fed because they finish off the kids buffet.
One year we hired 'Yorkshires premier children's party entertainer(trade mark)'. We have a very cheap community hall a few minutes away which cost about £20 with a full kitchen and we could set up/clean up outside booked hours and sort out food. She was bloody amazing. It was kids party boot camp, she obviously had an early years/primary background because no child would dare to go feral but all had the best time. She even had a headset. That party was planned like a work conference- games for an hour, sit down for birthday tea when she came around with temp tattoos (hand stamp) cake and happy birthday. Then a few activities before home.
And this is the best bit- about 5 minutes before the end and pick up she stated a game of sleeping lions. I was a bit WTF? However every time a child was out she was 'you are out, find your parent, get your party bag and thanks for coming'. Bloody genius.