Thank you for your reply, Limnos!
I will try the manual thing for the apps that may be not available (I guess no need to check messenger services etc. ;) ).
I appreciate your hint to the article, but this is where I came from and as far as I see it, it is not very clear on the results, e.g. what happens to purchased articles that are not available in the new store, what happens to stored iCloud data - basically the questions I had above. Maybe we see a different article (I have read it in German, English and Norwegian, but it says the same everywhere)?
I find the whole thing very confusing. The article states to end all subscriptions - but when I check my phone, it says I have no subscriptions (even though I clearly pay every month and also use the iCloud storage). This made me think that the iCloud payment is somehow a separate thing.
Considering that most of my photos are only in the iCloud nowadays, I would find it very weird not to retain those.
Not your fault, but why does Apple make this so hard? Isn't it quite common to move countries these days?