PS

*kbs - to tread (Kogan 2015: 296)

PC
*kbs - to full, to wash clothes (Kogan 2015: 296)

Akkadian
kabāsu - to step upon; to make compact; to let time pass (CAD K 5, AHw. 415)
Arabic
kbs - to full up ditches; to complete years by intercalary periods, (II) ‘to squeeze, press together (WKAS K 28‒29)
Soqotri
kébos - to fill in (LS 213, CSOL II)

probably connected