Yes you don't need the dongle to load SX OS. That's why they chose to sell the OS by itself without the dongle for those who wish to save a little money when playing backups.
Part of me wants to say no, but that's a responsibility you have to accept when dealing with products that border on being legal. There's a reason why Action Replays and devices similar are no longer sold in chain game stores. If you want to stay up-to-date with fellow users about the status of your SX product from there, you can visit this thread:
https://gbatemp.net/threads/3ds-flashcard-sx-pro.507996/
Jigs don't have a 100% success rate because of variations in the way manufacturers stick the metal into the jigs. If you want to experiment with other methods, you can find them here:
https://gbatemp.net/threads/the-ultimate-list-of-mods-to-enter-rcm.502145/
You mean like a replacement Joy-Con Rail for the Switch? Or like the jig that slides into the rail?