I am helping a friend with her thesuarus problem, I was able to recreate the issue on my own virtual machine after having reset my user profile
In my original installation the german thesausrus was working out of the box.
In the language and writing aid settings the thesaurus (mythes)was activated and it was available.
After i had reset the user profile
cd ~/snap/libreoffice/current/.config/libreoffice/4 mv user user-20220131
and restart of libreoffice libreoffice was set to language English(US).
In the setting the thesaurus (mythes) was activated and available for English(US).
When I changed the ui languag, the schema and the default document languag to German, I found that the thesaurus was not available (on right click it was greyed out).
Checking the language settings and writing aids, I found that for german the mythes thesaurus was not more available.
When switching back the user profiles thesaurus was back again. So it must be hidden somewhere in the user profile, any idea where to find it.
With my friend, the thesaurus is not working at all, so I want to know where to search further. Possilbly simpy changing a file or replacing it.