You can update locally. There should be an option when you press (+) on the game icon to update with a nearby console.
I use
JKSV. Unfortunately, I don't have any experience with emulators so hopefully it can import the save data from Ryujinx into your console. Also make sure that you run the game at least once on your console if you're importing save data for a game you never played on the Switch.
Do you have the patches to launch and install backups? If not, you can download them from this
thread.
You don't
have to dump the firmware files. You can download them illegally from the Internet if you want. Otherwise, you can try dumping the firmware files with the homebrew application,
biggestDump.
I would recommend following that guide. Just to clarify, your SD card is formatted as FAT32? If yes, go ahead with the unbricking guide. If not, try using FAT32 first.