Not the guy you were talking to, but I've talked about this in length in the past, here are a couple of my posts about this subject:
https://gbatemp.net/threads/xecuter-sx-pro-intial-setup.516619/page-2#post-8266478
https://gbatemp.net/threads/question-regarding-cfw-and-ofw.517013/#post-8259467
But
the relevant part is this:
It doesn't matter what CFW you use, whether SX OS, ReiNX, or RajNX. When you make a NAND backup, this is like making a "save state" of your Switch's current state. So you can undo anything that can leave detectable traces of hacking in your NAND by restoring your backup. As long as you've never gone online since the backup was made (because logs going missing is ALSO detectable, as people have been banned for clearing their logs before).
I recommend using Hekate ONLY for making the backup, since it has been tried and tested, and is the most reliable way to backup AND restore your NAND (even tools like ReINX toolkit have reports of NAND backups failing like
here, just use Hekate).
Also note, when you restore a NAND backup, you lose all progress in your saves (or any new saves) since the backup was made, you lose any newly installed games and/or updates since the backup was made... it's like your Switch went back in time to when the backup was made.