Usually you use an ID in place of the title of the note, because you may want to change the title at a later date. If you were to change the title, then you would have to also change any of the links. Therefore, you keep the ID the same and can change the title of the note without breaking any links.

So, just rename all occurrences or create a named hyperlink? Why do we keep coming up with already solved problems.

They're unique. Zettelkasten titles can be quite long: "Practices for nurturing healthy brain development during pregnancy" takes up a lot more space for a link than a 14 digit ID. You may say to just use a keyword of the title instead of the whole title, but then it is no longer unique and you must come up with another way of identifying which note it links to.

Also, using IDs means it is very easy to visually scan a note for links. The [[##############]] format stands out vividly.

I like it, it doesn't bother me. Do whatever works for you.

Is there a way to see a title or can you only show the ID in the preview on the left? I am very confused by this software because renaming a file brakes all my links... And if every file as a date as a name I would not know where to start.

I don't personally use the software that the OP mentions, so I'm afraid I can't answer that for you.