Upgrading Grafana from binary tar file without losing Dashboards

Hey,

I want to upgrade my Grafana from V.8.5.1 to 9.1.1.
I want to do this with the binary tar file because the server does not have access to the internet. In the Grafana documentation it says:

If you downloaded the binary .tar.gz package, then you can just download and extract the new package and overwrite all your existing files.

But when i do this, all my dashboards and settings are gone.
Does anybody maybe know what I am missing?