Lag and disconnects on all servers

I have combed through a long list of other problems similar to mine but have found zero solutions so this is my last resort. I've had this problem since I started playing online. There's a serious lag in all servers I play in. The servers work fine until I play a game. Once in game, interacting with other players makes the game lag tremendously. I can run around fine but once I start fighting a player it becomes all about luck and guessing because the character is just appearing at random locations as I try to defend myself. I've checked my internet connection extensively, tried other online games, even connected via ethernet, all to no avail. I have the game on my cell phone as well and the same exact issue occurs. When I first started playing the issue wasn't so bad that it would prevent me from playing but it's escalating with each passing day and now I'm at the point of playing only 1 or 2 games because they have no pvp. I now get kicked from the servers on a regular basis and playing with friends in their world's is a headache. I've tried a vast array of technical fixes like changing my router's channel to creating a static IP. I'm completely at a loss as to what else I can do and I'm hoping someone here can help. Thanks.