I also had a look at https://feddit.org/c/main but my German is very basic, the most interesting topic seems to be a tutorial on how to migrate accounts from feddit.de to feddit.org
Even though feddit.org is largely a German instance, content in English is also welcome. I believe that this has already been included in the sidebar.
I would also like to mention that feddit.org was founded in conjunction with the Fediverse Foundation. This is a non-profit organization from Austria that runs various Mastodon instances. There is active and passive association work and also a larger team that takes care of hosting.
The current problems of feddit.de in particular are due to the fact that the load is spread over very few shoulders and some of these are currently unavailable.