You might laugh at this but I find a quick rp with someone will often times shake the cobwebs off writing, or taking like say three days or a week and doing just a short drabble challenge on random words or insp lists. only 200 words or so, it helps kick your brain over to the right side. If your stuck on how to work out dynamics rp can help as it gives you someone to bounce a scenario (doesn't have to be related to your story) and see how they reply. That usually helps me out when i'm stuck or just stale.

Personally I find reading other stories helps me, songs, dramas are my goto as well. Usually I just wait it out, can't force it cause nothing happens. It's frustrating though, you want to write and nothing comes. Sometimes it helps to bounce ideas off someone else, they can sometimes give you a different perspective that will help you to come up with ideas and such.