The holes will have to all be drilled out a minimum of the thread diameter plus a a couple thousands until the hole is clean and smooth.
Then you throw away all the screws that were in them and replace them with the next size up closest to the new hole size. They should be the same type of material as the screws that are removed due to thermal expansion and avoid a fire hazard. That might be tricky
Then retap the holes to match the new screw sizes. Where this now gets tricky is the wall thickness between the two holes will be reduced by the difference in the diameters. You may be okay, but there is not as much material there to take the load.
It’s maybe doable. When you get ready to use new screws, when selecting the closest size look for what’s available in Metric and Inches (electricity doesn’t care) so you remove the least amount of material, may have to drills and buy taps to match.
Not sure how much the electrical load will be, but those look like stout cables, for safety reasons - I suggest buying replacements rather than risk an untoward event with worked over connectors.