I wish they would restore stopover functionality on the international booking site (https://www.international-bahn.de/). I remember back when you could book a London to Berlin fare (for example) with Eurostar included, with stopovers up to 48 hours along the way. Amazing value for tourists - often you could visit multiple Belgian/German cities for not much more than what the Eurostar fare would cost alone.

The standard bahn.de site still allows stopovers, but since the pandemic you can no longer book Eurostar segments through it. Sad face.