This door in Sapienza won't unlock from this side. Leads near the kitchen area in the Caruso mansion.

Then just go from the safe house and open it.
Or infiltrate from the big tower on the other side. Or go through the tunnel or by the coast

i know but even with a keycard it won’t unlock
and this is a problem

Confirmed on PC wwwwww
Already reported here HITMAN 3 - Bug Report Thread - #61 by MrBarnbeers