You said you installed RetroArch NSP but deleted it before you went online? That's a red flag right there, if your not banned yet, expect one pretty much soon, not all cases are the same so some will be banned sooner while others much later, even playing XCI files gets you banned like one of the members who replied here. Just too risky to be playing backups, installing NSP's then going online even if deleting NSP installed games.
Since you weren't using EmuNAND and just SXOS CFW, what you should have done before you went online is to restore your clean NAND backup, just deleting RetroArch wont remove all traces that this was ever installed.
Using SXOS, the ideal solution would be, restore your clean NAND backup then create EmuNAND as hidden partition (alternative is EmuNAND as files on SD CARD).
OFW: Use this as your legit game cart playing, eShop and other legal stuff.
EmuNAND: Use this for all your backup games, nsp installs, and homebrew stuff and STAY OFFLINE.
I have the above setup and not banned, I could get banned by I think my chances are pretty low, as far as OFW is concerned, it doesn't know I have EmuNAND. But any method is not 100% proof.
If your using homebrew stuff, it's recommended to have your SD CARD as FAT32 as using exFAT can corrupt your SD CARD, from what I've read, this only affects for those messing around with homebrew, however playing XCI and installing game NSP doesn't seem to corrupt cards that are exFAT, but anything is possible, but exFAT seems to be the most common file format that causes card corruption. If you have EmuNAND as hidden partition and your card gets corrupted, only the active partition is corrupted, simply just reformat the SD CARD again and start over, your hidden EmuNAND will still be intact.