I am Chinese user. When I type Chinese character to search my diary, it said no result. Some of the chinese word can be detected, but the diary text start from 2020, even though the related keyword has been written on 2018. i had recorded a lot of diaries and important message in Diarium.
However, all good in english word searching.
Diarium version: 2.7.6
OS + version: mac catalina 10.15.7