We just had our back-to-school night for the Montessori that we send our kids to, and the teacher talked about how proud the kids get when they are able to learn and finish something. They feel really grown up. Because it is Montessori, they are explicitly explained a job and then asked to do it, but for much of the day they get to choose which jobs they play with. They're called "jobs," but they are really just tasks or games, and we love this.
We explicitly did not want to send our kid to a "play-based" daycare, and recently I'm ever more convinced we're correct. A friend who did send their kid to one said the teachers there were super proud that they don't teach the children anything. They told them, "By the age of five, maybe we'll let them know what 1, 2, 3, 4, 5 is, but don't worry, we will never ask them to learn to write it or anything like that."
I find that totally ridiculous. Research shows that if you challenge children, they actually love it. When you define play so narrowly as not learning anything even slightly "academic," just playing with toys, props, or whatever is on the playground, it misses the point: learning should be play. To kids, learning IS play. It's nonsense to define learning how to write, for example, as "not play," and in the US, somehow increasingly "not OK."
And by the way, some kids like worksheets. There's this one five-year-old in the class that, in the pictures I've seen, they make up math problems for themselves to solve during free time. And others might be taking a book and trying to read it together. To me, refusing to teach them how to write with a pen and paper is just as stupid as forcing them to write all day.
And mastering something is how you gain real confidence, not through this fake "I am great, I am special, I am smart, I am unique" mantra that I see teachers having kids repeat to themselves. The more you figure out how to acquire a new skill and do it independently and autonomously, the more confident you become. That's true for everyone, whether you're 3 or 80.