How to Stop Spinning Your Wheels and Write
First: mental health is real. If you are in burnout, take care of yourself because if you push yourself in burnout, you can prolong it. You might want to try some of these things to keep being creative during burnout, but don't force yourself.
Try more creative outlines. I don't outline the way most people think of it. I outline with moodboards that nobody but me can understand, including main characters, relationships, side characters, and aesthetics. It makes sense to me and, when I look at it, I know exactly what I want each picture to do and say and why it's in the space it's in. If you are more visual, you can try that or a Pepe Silvia-esque string board. You can even try a playlist that is one song per chapter to convey the mood and repeat songs as needed. Don't take forever to do this; spend no more than a day or two and then get to writing.
Instead of a character sheet, writing the same scene from the POV of every character in a given chapter so you learn more about them. Character sheets can get some of us really in the weeds and we focus so much on whether or not our characters like punk vs classical music and certain fashion tastes that are ultimately not going to be on the page. That's not to say knowing these things are bad, but you can also get to know your characters by writing how they view each other and certain situations and by doing that, you also learn their motivations in each scene.
Just write 100 words a day of the project. That's it. Or a page in a notebook or 15 minutes of a sprint. Give yourself a small, reachable, tangible goal where you can see your writing grow. 'But I don't know where the story is going!' That's OK! It doesn't have to be perfect. You can write four pages and realize it's going nowhere and then cross it all out and start again. Pros do that, too.
If you're writing SFF, identify if you have Worldbuilder's Disease. What is this? It's when you spend all your time building a world for a story and you never get around to the story because the world isn't 'finished'. Tolkien didn't finish building his world. Last time I checked, GRRM never created more than 7 words of High Valyrian; David J. Peterson did for GOT. If you have Worldbuilder's Disease, make a checklist for what you absolutely need and if you have 75% or more done, you write and worldbuild on alternating days until you have what you absolutely need. By then, you should also have a better understanding of your characters and plot. If worldbuilding is your passion, you don't have to abandon it; but if it's stopping you from writing the story you want to tell, at some point, you do need to stop focusing on the worldbuilding and on the story.
If your perfectionism is the problem and you feel that draft one has to be perfect, this is going to be harder for some people than it is for others. For some people, accepting that draft 1 isn't going to be the end result is by calling it 'the shitty draft'. For others, it's by doing a draft zero, which I believe comes from screenwriting, and you write an unstructured draft with all your research and pants the hell out of it. For some people, that is draft one, for others, its a way to trick their brain into not putting too much pressure on themselves. Let yourself infodump in the draft if you have to. Get a cheerleader or enabler.
Get yourself an accountability buddy. Find someone in your friend group who also has a novel they want to write or a piece they want to learn how to play or a game they wanna finish, set a date for when it needs to be done that is reasonable, and check-in with each other. New Years' Resolutions don't work for most people, but cheering on a friend and them cheering you on and having someone who will ask you 'how's the book coming?' and listen to you when you talk about the best and worst parts of the week can be really effective to stopping yourself from going back to spinning your wheels.
Get a critique partner. Can be someone you met in fandom if you both are coming from the fanfic world or critique circle or a writing group in your area. If what you need is feedback, put yourself out there to get it.
Carrot method. If what you need is a treat, find a treat within your budget. Some people get a cupcake on Fridays if they met their writing goals four days in a row. Others treat themselves to a literary magazine subscription or a new hardcover book if they hit their goals for the month. If what you need to do is watch an episode of your favorite TV show after writing 800 words that night, do it. My personal variation of this is writing 500 words of the main project before I can work on other projects. Some days, I never get to the projects and others, I breeze right through and then get to do a whole short story I've wanted to write all week.
Fill in the blank method. My strongest points are dialogue and dynamics. If I forced myself to do internal things and description and sensory details down to the last detail on the first draft, nothing would ever get done. I give myself leeway and write the dialogue and dynamics and add the things I have to later. The more I practice internal aspects and description, the more I just do them, but I don't pressure myself. Pressuring yourself is not the answer.
Start in the middle. Starting is hard; many writers start in the wrong place, especially on their book. Some people do have a better sense of where a story should start than others, but some people have a better idea of what a strong finish is than others. Maybe your strength is the finish line. It's OK to write the last half of the book first and then add the first half. The first few chapters are almost always the chapters that are rewritten the most; that's why they tend to be the strongest and tightest.
