I'd argue you need between 6 minutes and 6 years.

It depends entirely on what you want. You can literally code a JavaScript 1-liner that will make a <textarea> then put the content back in the URL and it will work serverless on pretty much any platform with a Web browser.

You can also write a note taking app that will be federated yet private, that will have its own scripting language, etc. I mean you can yak-shave your way to write your own OS or even designing your own CPU for that.

So... I'm not sure that metric, time, means much without a proper context, including who does it. It's quite different if to do that, regardless of the tooling used, if you are a professional developer, designer, fullstack dev, prototypist, PM, marketer, writer, etc.

> Can you expand on this?

sure. does your note taking app supports formatting? you don't need it today. you will need it at some point. images? same.

does it handle file corruption etc? no? then its pretty much useless.

does it work across devices? in modern world, again, it is pretty much useless without it

it works across devices? then it needs hosting. if it is hosted it needs auth, it needs backups

you can go on for ever.

the bar for very minimal note taking app that you actually will use is very high, with other software it is even higher.

and this is not even state of art, this is must haves