Hi Sonrai!
Oh, this does sound like something broke on the motherboard OR power board. I would advise to check the fuses first. More information and pictures regarding the location can be found here (he is facing the exact same issue as you have and he fixed it with a new daughter/power board):
https://gbatemp.net/threads/new-3ds-xl-f....
Otherwise, try to replace the power board first (this one is way cheaper) if this didn't worked, then you do need to check the motherboard.
Replacing the power board guide: https://www.youtube.com/watch?v=KgBQoIw-...
Part can be bought here: https://www.aliexpress.us/item/325680586...
Good luck!!
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