Mateusz Konieczny
I would set correct opening_date at https://www.openstreetmap.org/way/172699280#map=18/47.49901/19.04375&layers=N

https://wiki.openstreetmap.org/wiki/Key:opening%20date "An approximated date in the future when a construction will be finished"

Note that start_date=* is for what opening_date is used right now