Pihole lost its static IP adress - not reachable anymore

@MichaIng beat me to it but here is mine anyway:

You could temprarely assign/add an IP manually until get it fixed permanently/reboot persistent.
And can even install a default route if want the host to be able to connect to the Internet.
That way you can SSH in again.
Example below:

When can SSH in again, post results for below ones here pls?

journalctl --full -u dhcpcd | tail -50

grep -v '^#\|^$' /etc/dhcpcd.conf