String to Date & Time does not convert

Hello everybody,

I need to perform an analysis of receiving data which includes the year and the week of the receiving data in the format yyyyww.

Following steps have been done so far:

transform data from number to string (number to String Node)
separated year and week with the String manipulation node and added a W to the number of the week and a -1 to create a day in the week (recommended hint by MS Copilot)

substr($Lieferwoche$, 0, 4) + “-W” + substr($Lieferwoche$, 4, 2) + “-1”

Than tried to create the date column but failed

I have been asking the KNIME-AI and MS Copilot but none of the hints could solve the problem. I have attached a file with some more details.

It would be great if somebody could help me out

thank you

Gerald