I think it’s probably child dependent and you’ll know what’s right for your children. We didn’t have an option when mine were starting out. The girls started school at 4 plus 1 week and 4 plus two weeks.
They’d both had good nursery experience (one with same cohort one in different setting). Their nurseries were quite formal with French, Reading and writing, ballet, school lunches etc.
They were both clearly quite able, could read, could do basic maths, could focus, could follow instructions, could put on tights and use cutlery. They were continent and able to go the lavatory by themselves. If they couldn’t they might have not settled so easily.
They managed just fine. One thrived and ruled the roost. One was a bit apart from ‘the gang’, but always has been because she prefers studious activities to charging around a playground. She had friends well enough, but until she was at medical school and found others like her, she didn’t have soul mate type friends.
The youngest is small. She’s was 95th percentile at birth but by the time she started school she was below 10th and is now, as a young adult about at lower limit of normal size wise. For her it was rarely a disadvantage. She’s supremely confident and gregarious. She gets irritated when offered children’s tickets still but there are worst things.
The older one joined an established group which was more challenging. Her nursery was very small classes of about twelve children. Always calm. She entered a class of thirty and found the general pushing and shoving in cloakrooms and wide open playgrounds a bit tough to start with but found her place well enough. It gave her a grit and determination that I’ve yet to see equalled.
I don’t think you can base it on what was right for other children though. It has to be right for your child. Mine might not have fared so well if they were less able or less confident.