I encountered an old Debian system and tried to upgrade it from Debian 10 (buster) to Debian 12 (bookworm).
During the apt-get dist-upgrade it did run into a problem, where libcrypt.so.1 was removed and the upgrade failed to continue.
Additionally this caused that dpkg itself also stopped working and that sshd stopped accepting new connections.
Thus fixing the following error became urgent:

/usr/bin/python3: error while loading shared libraries: libcrypt.so.1: cannot open shared object file: No such file or directory

Luckily I was not the first person to run into this issue.
In a Stack Overflow answer I found the crucial workaround taken from a comment on the corresponding Debian bugreport.
The following steps allow to manually install a copy of the missing libcrypt.so files to fix the issue (when running this you might have a newer version of the package at hand, thus adjust the dpkg-deb step accordingly):

cd /tmp
apt -y download libcrypt1
dpkg-deb -x libcrypt1_1%3a4.4.33-2_amd64.deb .
cp -av lib/x86_64-linux-gnu/* /lib/x86_64-linux-gnu/
apt -y --fix-broken install