I use the one inside the Switch to charge and have ready the Pro Controller I'm not currently using. When the one I am gets a lower battery, I swap out the charged one with the low battery one and continue on. Otherwise, that's been it.
When I got my Switch, I did get an internet LAN adapter with it like Adrock has referred to but I've never used it. I probably should but whenever I have done online gaming, I never think about getting it hooked up.