In my experience the Sparkasse is pretty decent, but since they're regional institutions YMMV.
> it seems like the low card fees in EU means much worse customer service compared to the US, or is it just my wishful thinking?
We just don't have much credit card usage since SEPA-ELV works pretty well. SEPA Direct Debit stuff you can chargeback at almost all institutions via online banking or self-service ATMs, credit card depends on your institution.