A few years ago, I backed a project on Kickstarter for some lovely Bluetooth buttons. The project completed successfully, and I’ve got one on my desk right now. They’re gorgeous:
And, you can still buy them. https://shop.turntouch.com
You pair the unit with software you run on your Mac. Once paired, the meaning of the four buttons can be customized in the Mac app. The buttons just send out a simple signal; all of the smarts is in the Mac app, which is pretty decent. More details about what you can use them for here: https://shop.turntouch.com/pages/how-it-works
To specifically answer your (O.P.'s) question about being able to trigger a curl request: Yes you can! Indeed, that’s all I use it for, making curl requests to webhooks I’ve set up on my home automation system (Home Assistant, not HomeKit). Here’s an example:
(New user, can’t post a second image, alas. I’ll see if I can in a second comment.)
At $39 each, they’re not cheap. And you’re dependent on the software continuing to work, I suppose. But they are lovely to look at, and handle, and very flexible. The battery is easily replaced. I expect to be using mine for years.