These days there is very little difference between the major brands, in fact a lot of us refer to as Canikony, (it used to be Canikon until Sony came along). So the 6D is fine, in fact, great.
I occasionaly run workshops for photographers and the thing I try to get into peoples heads is that the equipment is only a small part of the equation. The most important part of photography doesn't involve the camera.
It involves your eye and brain.
As someone said, "Most of the worlds greatest photographs were taken on equipment that would be considered unacceptabile by todays standards." I use lenses (and camera designs) from before the First World War at times.
Don't sweat it in other words. Get out there and use the gear. Keep your kit as light as possibile, wear comfortabile shoes, and play. Make sure you enjoy yourself. Later, look at your photo's, see what went right and what didn't. Look at photobooks, websites, and find images like what you want to make and reverse engineer them. Work out what they did. And then try it yourself. Best way to learn.
And to start with I would suggest one lens. If you have access to the metadata from your old camera look for the focal length you made the majority of your pictures at. That can give you a guide as to the focal length of the lens to get. Most often it will be at either the widest or longest of the zoom length. Get a fixed focal length (or "prime") at that length. (Fror me it has always been a 35mm equivalent). At the most get two, a wide (say 28 or 35) and a short tele (a 85 maybe).
But most of all, have fun!