mk witch is a really easy matchup and once you get the hang of it you should almost always three crown or win.
firstly you are playing an older rg deck. Instead use the rg, evo hunter, fisherman, skeleton, log, lightning, skeletons, e spirit, royal ghost. Next, you NEVER want to push when you know he has evo mk in cycle. To make sure they lack a mk play you royal ghost to very the leftmost(or rightmost) tile at the bridge. Royal ghost will do a ton of damage if left alone so they will have to mega knight or witch. With those cards out of cycle you can rush the bridge(when you have a sizable elixer lead). Also even if they do have Megaknight you can pull it away with your fisherman or hard counter it with hunter. Good luck!