When I was teaching programming my go-to was the JavaScript canvas api. It’s 2d only, and very simple. And being on the web once a student has made something we can host it for them and they can show their friends.
I have a ~20 line html harness which sets up a page with a full screen canvas element and gives you global window width & height variables. That’s all you need to get started. And it’s real JavaScript - so students learn a useful programming language as a result, and the advanced students can go nuts and add sprites, sound and networking if they really want to.
I tell people to leave the html file alone and edit the javascript, using the canvas API to make it draw whatever they want. Canvas supports text, shapes and images and translations / transformations. If they want, I show them how to animate their work as well.
Another option is to use the p5.js library. They also have a nice online editor, at https://editor.p5js.org/, which makes it easy for students to get up and running quickly.
I have a ~20 line html harness which sets up a page with a full screen canvas element and gives you global window width & height variables. That’s all you need to get started. And it’s real JavaScript - so students learn a useful programming language as a result, and the advanced students can go nuts and add sprites, sound and networking if they really want to.