Ok, if you have that much free space, perform an upgrade WITH MY20 protection enabled. Since your unit is EU and F10 maps are not locked, you can install them without reformat.
Just make sure it’s not a reformat install.
Also, read the tutorial, since an AUTOINSTALL for MAPS takes a long time and multiple reboots (do not interrupt the process)
EDIT: The tutorial is for NA, but the general principle applies to EU as well → Tutorial: 2020 North America 2.20 Map Installation (Stand-Alone without Reformat) with Updated NAV_Voice 06/21/2021 . That’s a manual method, but Syn3updater can create that for you now.
EDIT2: Maps are F10, not F20… Fixed the typo…