Well, I don't know about the red 3DS XL, but I jailbroke my blue 3DS XL. Actually, it was my wife's. She was never really a gamer, but she wanted to be one. She bought it, played it for about a week, then it started collecting dust. Same with the Switch. I can't believe how many hours I put into Animal Crossing. It wasn't out of spite, either. Anyway, yes, you can jailbreak your 3DS XL, and it's pretty easy to do. There are some pretty good guides on YouTube. I'm not delving that far back in my history to find the one I followed.

The 3DS XL takes SD cards, not microSD. However, you can put the microSD card into an SD adapter and it should work.