Starting Fresh, Concerned About Losing Things

Okay so the short of it is I bought TemTem, finally, around this time last year, played a bit and then got sidetracked with life or more likely other games. I wasn't far at all, maybe the 2nd town or around there. I want to finally play it and start over so I can relearn everything but I'm afraid I'll lose SOMETHING I can't get back or something like that. (Like how in Pokemon, specifically BD and SP where you could only get Shaymin while the item to spawn him was a mystery gift so if you restart it's fine forever, which I did a while back lol) I know for a fact all I really did was enter a bunch of codes for items and clothing, started the last battle pass (before you were able to just have them and work on any one you want at any time) and had the deluxe edition. I guess my question really is: if I start over will I lose anything I can't get again? Will I be able to reenter all the same codes or will they not work this time? And should I just make a new profile on my Switch and start a new file to relearn the basics then just go back to my main file and try to continue it?

I appreciate anyone who reads this meds and understands what I mean, I know it's a bit all over the place but I tried to get my point and fears across lol. But thanks in advance! 🙏