How do I unstall and start over properly?
If you're on emuNAND, you can just format the SD card and start from scratch. Not sure about sysNAND, though. If you've installed any pirated games, forwarders, etc. directly to the sysNAND i.e. Switch internal memory (not to be confused with the emuNAND's "NAND" partiton which is stored on the SD card), then it's definitely "dirty". The only way to get it back to being "clean" is to restore a previously made backup of a clean NAND.
In case you'd like to backup your games and restore them later sometime, you can use
JKSV to do to that.
Before you start following any of the written guides, check whether your SD card is legit or not with
h2testw. It's a lengthy process but totally worth it. Imagine doing the whole console hacking thing just to end up with your system, files, etc. going corrupt shortly after due to a faulty/fake SD card.
I'd suggest that you follow either
Rentry.org Switch guide or
NH Switch guide (my personal favorite) in order to softmod your console.
Make sure that you create a NAND backup just in case anything goes wrong during the installation process,
don't skip it.
if you plan on going online in order to e.g. download additional homebrew or play in local multiplayer, make sure that you set up
Exosphere's prodinfo blanking and DNS MITM as well. Check
here to see how to avoid getting your console banned.
For game backups to work, you'll need the latest
sigpatches (important!) and/or
sys-patch module (optional, it's currently discontinued due to being taken down by Nintendo, but it's still useful). Additionally, should you choose to install sys-patch as well, you can install
Tesla +
nx-ovlloader as well as they will allow you to see whether sys-patch is working properly, after you press
L +
D-pad Down +
R (Stick) combo, select
sys-patch, followed by
Log. It should say
Patched (if it's green, it's good; if it's orange, it means that it's already patched with sigpatches). Having both sigpatches and sys-patch at the same time should cause no conflict at all.
Why do you need to uninstall perfect cfw?
Personally, I don't use Tinfoil, only DBI. I don't use custom themes or cheats either
I do, however, use TriPlayer (audio player) and NXMP (video player) on my Switch and a couple of other homebrew apps.
I also prefer the standard Atmosphere boot screen.
I wouldn't say that Kefir is perfect, but I do see its value. It's a decent solution for those that want a simple all-in-one solution, without having to worry whether they have everything they'll need or not. Sadly, those packs usually come with some extra stuff that most people won't be interested in or not use at all. Therefore, potentially introducing unnecessary clutter.
If you know what you're doing/getting, go ahead and pick one of those packs. It's much easier to troubleshoot your setup when you have less files to worry about.