I think what you need is inspiration, there’s so many things to build to improve your skills and broaden your knowledge. Not every project you work on needs to be novel and exciting, even basic things can provide ample complexity to learn new things.

For example, in c++ you can make a basic image viewer that takes the name of a file and displays it, using some library like SDL (or OpenGl/Vulkan(hard)). This would teach you a lot about file formats, dynamic memory allocation and managing it, graphics pipeline etc.

For html and css, you can try to recreate some cool websites you see online. I hope this gives an inspiration(best viewed on PC).

For problem solving there’s always leet code, advent of code and other similar services.

Here’s more stuff to get started

You have 5443200 seconds to make your choice.

Is macOS different from linux(in command line things and such, not the GUI)?

Yes, but the person asked comparing to nano…

• Teleportation: the cursor can be teleport to any line without pressing down key multiple times…

• Macro: for repeating a sequence of inputs multiple times…

• Tabs: nano can’t open multiple files at once i believe…

• Split screen(horizontal and vertical)

• Themes and plugins

These are a few that comes to mind…