Whatever you do, remember that kids have accidents. Even older fully pee and poop potty trained kids, have, accidents. It is childhood.
Per my daughter's Preschool/Kindergarten/1st Grade Teachers, kids at these ages have and can have, accidents. And they do. The teachers deal with it...by not making a big deal of it. Even at my kids' school, the health room has stocked, clean extra clothing (shorts/slippers/undies) for the kids that have accidents. This is, Elementary school. The younger kids, have accidents. My daughter in 1st grade, had a couple of accidents, and even in Preschool and Kindergarten. For example.
My daughter potty learned early.
My son did so later, when he was already 3.
Both are normal.
Boys are often... later.
And each child, is different.
But the commonality is: if you make it a "battle" and a bribery thing, it will NOT make the process any quicker or any easier. Nor will it make the child's physiological organ development, readier.
Then for night time and sleep/naps, this is a separate, timeline.
Nighttime/sleep dryness, is something that does not occur even until 7 years old, and is completely normal. So at night/naps, nighttime diapers are still used. My kids, NEVER ever, got "confused" about wearing diapers for sleep but not during the day. Because, I simply explained to them... that their body... is still... developing.
It is about brain/bladder/hormonal/myelin nerve sheath, physiological development. Not about the kid's age.
With my kids, I went according to their cues.
My son as I said, was a late bloomer, but normal and per boys.
Even at 4, he was still getting the hang of it. I never pushed or battled him about it or stressed about it. He went to Preschool, the Teachers had no problem with it and they know it was normal. They were nurturing about it. And by Kindergarten, (he was 4 years old then turned 5), he was fine.
Completely, fine about toileting.
Again, having accidents, are normal. This is childhood.
And it is always handy and wise, to get a few waterproof bed pads, to put under your child for sleep. Even if they have a sleep diaper on. Because, then for leaks or accidents, it will NOT get the sheets soiled. I got 4 of them from Amazon.