I woke up and then spent Sunday afternoon playing Miitopia on the Nintendo Switch 2 for three hours, then in the evening I watched some episodes of My Little Pony Friendship is Magic. So I really enjoyed this Sunday!
The time and day changes are caused by the battery being incorrectly positioned in the 3DS, which is why the day, time, and year are reset every now and then. However, the battery only lasted 30 minutes at most unless I kept the 3DS charged.
I understand you, batteries usually tend to wear out and two years ago I replaced the battery in my 3ds xl with a new one but unfortunately recently between 2024 and 2025 even with the new battery the time and day shift randomly and the battery only lasts no more than 30 minutes. I think my 3ds xl is almost dead.