Well I was kind of playing on all game modes I tested top to bottom on minecraft settings whether it was render distance clouds settings music or anything I changed and played around with all settings, and still getting the same result. So this is an official bug that needs to be fixed. If you were to try to shoot a regular bow, just aim at anything, you wouldn't lag. But there's something with enchanted bows, when ever you aim to shoot, it causes so much lag, drops me down to 20 fps but it could do more to others. It is very annoying. I'm guessing the reason why Enchanted bows cause lag is maybe the way it flashes because when a tool is enchanted it shows a bunch of colours and textures of light on it, that could probably be it but for now I think I'm the only one who has realised this type of bug.