Only few or no contacts appearing in main search window

since ios 17, now ios 18, i cannot search for contacts. I.e. i have five people with the same family name but when i type the first name, search give me only one contact. Some contacts are not appearing. Thats really annoying! Before ios 17 it was working perfect, it was shown many contacts, even when i just typed 1 or 2 letters of a name. What wrong now?

[Edited by Moderator]