Yeah, using the Sysnand/sysmmc should be safe, either booting the switch normally, or booting the stock mode of hekate, as long as you never connected online to nintendos server in emunand.I have Atmosphere, i run everything dirty on my emuNAND and block it off with 90DNS. can i still use my sysNAND as always (downloading legit games from the eShop, playing online) or do i risk getting banned cause all the cfw files and dirty games are still on the same SD card?
Just make sure to check that sysnand/mmc prodinfo blanking is not enabled in the exosphere.ini, in case that you accidentally boot CFW on it, so you are note leaving potential traces.
Also just using CFW itself is not that big of a risk, since the normal atmosphere is build to be used while going online. So even if you boot cfw to easier switch between emunand and sysnand with overlays like fastCFWswitch or stabalise the framerate with something like sys-clk, you will probably be safe. Just make sure you don't install any type of nsp/xci to your sysnand, don't cheat or romhack online on your sysnand and don't use things like prodinfo blanking on your sysnand.
(I don't even remember when I last bootet stock, it was a few year ago, since then I'm always in sysmmc cfw to do things like streaming in discord and "overclock", while playing online)













