@Christian Koßmann
I aggree with HamidSadeghpourSaleh.
Here is the link "[New Microsoft 365 offerings for small and medium-sized businesses][1]", I think it is helpful, you may refer to the part of Frequently asked questions.
I think one of the important aim that Microsoft changed the names of Office 365 plans is to rebranding.
The branding shift is to better reflect Microsoft's ambition to continue to drive innovation (Such as the innovative cloud-based productivity tools, new artificial intelligence (AI) features.) in Microsoft 365 that goes well beyond what customers traditionally think of as Office.
But this is a change to the product name only, and there are no pricing or feature changes at this time.
Hope the information could be helpful.
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[1]: New Microsoft 365 offerings for small and medium-sized businesses