As you said, it is not normal to be 3 or 4mm longer than the next tooth, whether it is only in length or beyond the dentition plane.
It should be said that there are generally two methods, one is correction, and the incisors are arranged neatly by moving the dentition as a whole. The advantage of this method is that it does not need to damage teeth, and the overall arrangement of dentition is better after finishing. But the time is long, maybe two or three years, and the cost is high, five or six thousand.
The other is to make porcelain teeth. Grind off these two front teeth and put on a porcelain crown to improve the appearance. According to what you said, it may be necessary to grind more, and it may be necessary to beat nerves and do root canal treatment first. Moreover, if your teeth are outward, the effect of deformation may be limited. The advantage of this method is that it can take effect quickly in a week or two, and the cost is relatively low, more than two thousand. But you need to grind your own teeth, and you may have to kill the tooth nerve, and the effect of change is limited.
It is best to go to a professional stomatological hospital for consultation. For orthodontics and restoration. See what advice the doctor will give after checking your condition. I haven't seen your situation yet, I can only say it.