Have you tried dungeonmastersvault? It is really easy to use and with like half an hour on searching you can get all the source material in there

What gets my brain going is actually engaging with the subject. What I mean by that is the following: Let’s say I wanted to further my DnD World. The best way for me to to that is by either playing some myself or sometimes it’s enough to just watch some content related to DnD or Just worldbuilding. I guess what I’m saying is fill the brain with Stuff similar to what you want to do and the desire to do it combined with being already there mentally will do the rest (at least for me)