Antoine Oliver,
The 2GB limit applies to ANSI format .pst file. This format was used in Outlook 2002/XP or previous.
You can create a new PST file if you have a newer Outlook.
By default, a Unicode .pst can grow as large as 20GB in Outlook 2007 and 50GB in Outlook 2010, 2013, 2016, 2019 and Office 365.
You can use
Export Outlook Items to PST File utility to copy all items to a Unicode PST file.