Technology choices (language, framework, etc.) follow from requirements. Since you didn't give any requirements no one can give a meaningful answer. Your question is like asking "Hungry, what should I eat?" The stack you might use for a web site is very different from an Arduino project, and the stack for a to-do list app is different from that for a fitness tracker.

If part of the hobby project is to learn something new, then take your pick of things you're interested in. If your main goal is to get something working you should choose tools you already know.