Does someone know if it is possible to select multiple "error-features" in ArcGIS Pro Topology error inspector and fix all of them with the same solution (e.g. create new feature)? Currently in ArcGIS Pro 2.2.3 it does not seem possible.
Currently, in ArcGIS Pro 2.2.3 this is not possible; each error must be addressed individually.
It also appears you've added a suggested idea to the ArcGIS Idea site (based on the same screen shot): https://community.esri.com/ideas/15760-arcgis-pro-topology-inpector-fix-multiple
It's possible to fix multiple errors at once using the Fix tab:
This has existed in ArcGIS Pro since version 1.4. The workflow is documented here: https://pro.arcgis.com/en/pro-app/help/editing/validate-and-fix-geodatabase-topology.htm#ESRI_SECTION1_5ED07CFE7FCE4182A1334B7C249922D1
The fix tab was not available in ArcMap. In ArcMap, you had to make sure you were selecting errors of the same type in order to have the choice to fix multiple errors at once via the context menu.