Hi, my basement has several joists with multiple perforations, some on the bottom half of the joist, through which MC cables are routed. I am afraid that inspector will flag this and am willing to reroute the cables. However, the joist holes will be visible. How can I mend them?

Intalling a sister joists may be your best option, if not out right replacing the affected joists

https://extremehowto.com/fixing-a-damaged-floor-joist/

https://www.doityourself.com/stry/sistering-floor-joists-6-mistakes-to-avoid