How to get rid of split ends without losing length?

The truth is split ends can't be "fixed" in the sense of sealing them closed, you're gonna have to get a trim whether you like it or not! But don't worry, you only need to cut like half a centimeter or one at most every 6-8 weeks, it's barely anything and you practically won't notice it! In the meantime, use a hair mask or oil on the ends after you wash them, that keeps them in better shape and delays them from splitting more. Trust me, even though you'll be losing those centimeters regularly you'll end up with hair that looks infinitely better than if you leave it with completely damaged ends, it's totally worth it!

Technically speaking, that half centimeter they mention above is the minimum, but if the ends are really a mess like you're saying, you probably need a bit more - maybe 1 or 1.5 cm - so it actually looks good. What you can do is space out your trims as much as possible by using good conditioner and avoiding heat as much as you can, that way the damage progresses slower and you don't have to cut as often.