Warning: PDK_ROOT env. var. not found or empty, trying to find an open_pdks install No open_pdks installation found, set PDK_ROOT env. var. and restart xschem setup_tcp_bespice: success : listening to TCP port: 2022

This warning tells you that you need to set a shell PDK_ROOT variable pointing to the sky130 pdk installation. If you are not using a pre-packaged container then the pdk should be installed with open_pdks. export PDK_ROOT=/path/to/pdk