The solution is obviously to buy 24 clocks and set each one's alarm to a different hour

There's a line of clocks where each hour is a different bird and the chime at each hour is what that bird sounds like. It has a light sensor to control its volume so at night it's very quiet, never gonna give wake you up. Completely analog, for better and for worse.

https://www.audubon.org/marketplace/singing-bird-clock

It's not adjustable so I'm not sure it's a perfect fit, but it's lovely. They've been around for ages, I had one since I was a kid, I'm surprised they're still available.

Edit: it does tick like most analog clocks, which could be a deal breaker with ADHD. I know it's sometimes a bother for me.

I don't have an answer for you, but our grandfather clock goes off every 15 minutes, and I've found that really helps me keep track of the time and not accidently get sucked into any one thing for hours on end.

So, I totally get where you're coming from.

You could “build your own”. Use home assistant to play music or a sound bite on smart speakers around your house. Or even just have it send you a notification. Home assistant can run on pretty much anything as well.

Easy to do on your phone with an app like AMDroid that has very configurable alarms (on most android phones not sure about iPhone). Just set a good tone and set it to dismiss automatically after a second or two or turn off looping of the alarm sound.

There are standalone clocks that use Android and have a touch screen and all of that, but usually they are expensive and have low build quality for the price. I was looking around a few years ago for a bedside clock with advanced features.

It depends on your budget and location but Seiko makes clocks that meet your requirements:

https://www.seikoclocksusa.com/products/qxm615brh-melodies-in-motion-clock-brown.html

On the hour, the clock springs to life with motion and melody, playing one of 40 finest-quality sound melodies, each with opening and closing sequences that add theatrical flair. Complete with 22 sparkling crystals dazzle and dance as part of the clock’s magical display. Crafted with crystal glass for clarity and elegance, the Snow Castle Clock features: light sensor to automatically silence melodies and motion in the dark, demonstration button to preview the show anytime, volume control to suit your space,

I got a digital desk clock that I can set any alarm for. I do an hour at a time with the timer counting down right in front of me. It helps me trick myself into being productive as well as avoiding losing track of too much time if my mind starts wandering.

Growing up we had a wall clock that played a different bird call for every hour. It had a light sensor so it didn't make noise when dark. Maybe something like that could work?

Using home assistant and a smart speaker i've done what you're wanting to do. Added bonus is when going to bed I press a button to turn off most of my automations and the same button to turn them on in the morning. That way if my sleep cycle changes on the fly the chimes change with it. I've also got the added bonus of being able to use whatever chime or sounds i want.

But that's probably overkill for what you want, unless you want to pick up the hobby of home automation.

I can't recommend a specific clock, but I know a lot of mechanical clocks can do something like this where the chimes don't happen overnight. It's not a guarantee, but maybe something to look into

What about something like https://awakeningbell.org/ (if you are at your computer all day)