More than likely it has to do with the Windows regional settings that are set for your computer due to being in a different country than the USA.
Since you have found that the semicolon works for you, I would continue to use that wherever you see the comma.

Windows 10 region settings are found in Start -> Settings -> Time & Language -> Region -> Related Settings: Additional date, time, and regional settings -> Region: Change date, time, or number formats -> Additional settings.  Next to "List separator" is a comma for the US, and semi-colon for your country.

Ok, still weird that it's only with the period comma ; when I write code in a query, with SQL in the properties, or in VBA, a comma does work.

SQL statements are a special case, as their syntax uses only US rules.  For instance, dates use the US date format of mm/dd/yyyy inside an SQL statement.  If you try to use dd/mm/yyyy inside an SQL statement, Access will auto-convert it to mm/dd/yyyy if the month and day are unambiguous, like #31/12/2023# or #8-Sep-2023#.  If it's something like #8/9/2023#, Access will only see it as August 9th.