Follow a guide to make a todolist in a language that's popular for things you're interested in.

• Games - C# (medium), C++ (hard)
• Webpages/Webapps - JS/TS (medium)
• Microcontroller - Python (easy), C (medium), Rust (hard)
• Datascience and machine learning - Python
• Automate shell - Bash
• Automate w scripts - Python / JS
• Game mods - Look up for each game
• Android - Java
• iOS - Swift

For each make a UI and connect to any database that's convenient.

If you want to setup a server you'll need to figure out how to communicate via http.

Making a Todo list app covers most of the "mundane" programmer problems in each language and is a byte sized problem (hehe). After that choose something bigger or post again. Good luck!