Sounds like a lot of misconceptions have been given.
You don’t need to get any weird joycon, you definitely have everything you need. Either a right-joycon or a paperclip.
I’ve done both (and broke my spare JC in the process). I recommend the paperclip. [2:24 tutorial]
What’s simply happening is you’re sending power to a specific pin on your switch. When it gets power and you press the special dev-buttons (Minus-Volume & Power) it goes black and can be exploited with some tech-wizardry.
There’s some cool stuff like themes, homebrew, mods… Been playing Smash Ultimate online for years with mods. However, if you have the means on PC the actual gaming experience over the Switch is typically better and easier to get into.