The following repo provides a method of detecting connections through nwell or substrate. These connections are not flagged during normal LVS but result in greatly reduced drivability because of the high resistance of wells. This is intended to find errors that would be generated from SCONNECT command in Calibre. It requires magic and netgen but no pdk files (they're included). You should be able to

run_scheck <top_cell> <gds_file>

without any other settings. Feedback is appreciated. https://github.com/d-m-bailey/sconnect_for_sky130_magic