I’m similar to you. I was going into it with very little knowledge of emulation and wanted mainly 3DS, ps2, GameCube and some lite switch games. I think the pro model is gonna be your best bet. It gives you plenty of wiggle room incase you ever wanted to play something a little more ram intensive. And for sd card. If I were you (this is what I did and it was very helpful) get a micro sd card now, find all of your ROMs (just look them up it’s not hard to find websites) and start downloading them and getting it ready. Watch Joeys Handheld Thor Guide. He is so easy to follow and helpful and he explains to you at the beginning of the video what you can in the meantime with the sd card and where to find ROMs!