Bug prevents users from downloading programs

Do you use hacks? My suggestion is that you delete your 3DS.

Don't wipe your 3DS. That's an awful suggestion. Not only would it not even get rid of the CFW in the first place, you'd lose access to all of your save data in everything, even if you backed up your SD card's files, since they're encrypted and the key changes after a factory reset. Besides, removing CFW isn't the solution to this. If anything, you'd just be removing the only tool you have to fix this.

Uninstall and reinstall the game. As long as you don't delete your extra data, the most you'll lose are your editor colors.

Uninstall and reinstall the game. As long as you don't delete your extra data, the most you'll lose are your editor colors.

don't forget about the smile tool button assignment lol

SOLVED: It had to do with some feature of Luma that I thought would be unrelated. Thanks for the suggestions everyone.

What feature is it, in case it can help people in the future?

There's a cfw tool MBR(?) made which allows sb files to be decrypted and moved to another place on the SD card so you won't lose those -- made by Triangle https://smilebasicsource.com/forum?ftid=468&page=1