I have searched this problem and I found this:
If I change in the Joomla configuration the time zone to e.g. Denver (US) the filtering shows the date correct.
If I change it back to Berlin (I am located in Germany) the filter shows the date with - 1 day.
I checked the database. If I enter in my articles into the custom field "date" the date 2020-07-22 the entry in the database is 2020-07-21 22:00:00
All entries in the database are - 1 day and the time is either 22:00:00 or sometimes 23:00:00
I don't know where the time 22:00:00 or sometimes 23:00:00 is coming from and I cannot change the entries in the database.