There is a road-sign here signaling "No entry in this direction, except bicyclists".

It can also be seen on Google Maps for reference.

I suppose it's meant until the other marker I put, which marks a one-way in the direction of Bachstraße.

There is a street sign here "One-Way only, except bicyclists" pointing from here on in the direction of "Bachstraße"

It can also be seen on Google Maps for reference.

Unable to answer "What surface does this road have?" – Service Road – way/146125760 via StreetComplete 61.3:

Looks like private property

"Mathis closed 14.09.2025"
The place has gone or never existed. A CoMaps user reported that the POI was visible on the map (see snapshot date below), but was not found on the ground.
OSM snapshot date: 2025-08-22T03:20:49Z
POI name: Mathis
POI types: amenity-cafe
#CoMaps android