I used to run braid with leaders. After a couple of years of frustration I quit! Now I use straight braid, monofilament, or fluorocarbon line depending on the application. I only ever use one knot. It is easy to tie and quick. I can tie it in about 12 seconds with gloves on. It is called the 16/20 or Pitzen. I have been using it since some of you guys were still in diapers.
https://www.netknots.com/fishing_knots/pitzen-knot