SPO: How to configure default Locale (date- and timeformats etc)

[salbeck-sit]

The current SPO-resources don't seem to include anything to configure regional settings like date- and time-formats.
I'm tempted to take this on but I am unsure of where to start. Graph is notoriously lacking but PnP seem to have something (see https://www.sharepointdiary.com/2019/06/sharepoint-online-change-regional-settings-using-powershell.html).
Then again, if this isn't done at the beginning, multiple sites may exist and need changing as well - this could be optional.

Anyone tried this ?