Another option is https://roda.jeremyevans.net/, which I've found is the sweet spot in smaller projects, but can still scale up. The plugin system works really well to extend and the routing tree is really easy to work with.
We recently moved a legacy Rails 2.3 app over to the latest Roda, and paired it with Vite, Stimulus, and Tailwind on the frontend...and honestly, we couldn't be happier with how it turned out!