For me Pre-authorisations used to disappear faster than they do now.
For the last half year or so it has been a month - I can even see the date it 'expires' in my bank app/online banking.
Maybe it's my bank.....
If I have incidentals the whole pre-authorisation amount disappears when I am charged for the incidentials.

PS: I have never been actually charged too much of money in connection with pre-authorisation.