My two biggest suggestions are to focus on the local area and build outward as needed, and to know what your central tension is.

The first one is simple enough. Building a town and a goblin cave is easier than a planet and the realm of super magical evilness.

For the second one, central tension can be thought of as an underlying theme in your world. For example the main tension in my world is safety and stagnation vs uncertainty and progress. The gods keep us safe, but that also means we have no need to struggle and grow. Even though the players aren’t really aware of that even being a theme of the game yet, just knowing it myself can inform what kinds of characters and plots I set up as I continue to build more. When you know what the main conflict is at a more abstract level, you can see how certain characters might be on one side or the other without realizing.

I’d personally take a break and mix things up. See if someone else wants to DM, try a different game system, or even just hang out and play board games for a while. You can’t push through burn-out, and neither can the players.