Does it still light up and/ or the fan turn on?

Here is my question for you OP. I read through your post. How did the problem happen? Like what lead up to your steam deck not working?

Here is an example. You were playing it like normal. Then you forgot about it and let the steam deck battery get depleted. Go to charge it and it doesn’t turn on the screen but the steam deck turns on.

That is a theoretical scenario. What happen in your story to the build up of it not working.

I’m sorry this happened to a fellow steam deck brother.