Unless you have a clean NAND backup, you're probably going to get banned.
If you don't have a clean NAND backup, you may get banned, but you'll never know unless you try. There's no point in avoiding getting banned by staying offline if you're just going to get banned whenever you go online anyway. I'd recommend deleting all your installed titles, using Tinfoil to delete all your tickets (may or may not help), using nx-dreport to clear error logs (I know people will argue with me on that but in this case I think it's your safest bet), and finally doing a system format. Make a NAND backup, as this is probably as clean as your NAND is ever going to get, and try playing online. Stay away from SX OS, see if you're still able to play online after a week or two. If so, I'd continue making a restoring NAND backups as other people (myself included) have recommended around here to switch between SX OS and a "stock" setup. If you get banned, it was inevitable.