Lost luggage and other items can be reported either online at Deutsche Bahn or in person at the DB info point at EG.
Found items (especially important documents, wallets, phones, hand bags, etc.) should be handed over to the Info Desk if they seem to belong to a refugee.
Info Desk is going to keep those items around for 24hrs before passing them on to DB Lost&Found to prevent buerocracy for refugees who travel on.
So ask at the Info Desk first!
For lost ID documents (e.g. Ukrainian passports), besides to the report at Deutsche Bahn, please also let the Bundespolizei know! See also here.