I would 100% recommend anyone who is serious about programming to learn C first. The syntax is very simple and the language is pretty easy to use. It also gives you a peak under the hood at how all programming languages work because it exposes a lot of control to you.
If you are intimidated by the difficulty of C (which I don’t think you should be — the hard one is C++), start with whichever language matches your interest:
Web dev: JavaScript Game dev: C# AI: Python
But also, remember that a programming language is just that. A language you use to express your ideas. A skilled, highly employable developer will know many languages even if they only use one at their job. Always seek new information and try and advance your learning. The syntax of a language is a pretty minor part of the journey overall and the least important part for a beginner. It’s all about learning how to think and how to express complex processes in a way the computer understands. The language just tells you what words to use once you can already do that.
I can’t give you what you’re looking for, but the great part about challenges like this is that they are real problems to solve with input data to deal with.
You might try reorienting yourself, then. Instead of trying to teach your students the perceived “point” of each problem, use the problems to teach them about common design patterns and any algorithm that might apply that they don’t already know about. It’s not necessary to present the “best” solution and algorithm to each problem and only teach that, in other words.
I used one from a couple of years ago to practice dealing with first class functions. Would’ve been wildly inefficient at run time, but I had a fun time returning functions from functions and trying to use that to make really modular, overengineered code. And I feel I have a better grasp of that concept because of that experience even though it probably wasn’t how that problem was intended to be solved or even a good solution to it by any stretch.