Are you saying the electrical system hasn’t been updated in 70 years? If so that may be the problem.
Listen, it worked for 70 years, why would it stop now? ha!
Im saying after local power fixed underground electric line to building no one knows if building is grounded properly. Yes at meters. Yes at boxes. That is individual unit responsibility BUT SURGE WENT THROUGH BUILDING, knocked out units computers tvs cable boxes phones etc. No one knows if building is grounded. No local city gov or King county gov or state of WA official at WA Labor & Industry can tell me law or rule MANDATING owner check ground AFTER SUCH AN EMERGENCY. So basically YES no update to ground of entire building in 70 yrs. Condo w an HOA.
Sounds like you need an attorney to explain the laws as it relates to fault for the surge and destruction of property. A licensed master electrician in your area should be able to answer the rest of your questions.
I don’t see that a licensed electrician or engineer has been hired to look at the system. Is there an issue with hiring a professional to inspect the entire electrical system? Even if the utility upgraded something on their end did they change anything within the building?
That happens frequently, even in " properly grounded systems".
No changes within building --except new cable lines needed & broken computers tvs radios phones modems etc. CRAZY SURGE. Alkilinity of soil deteriorated underground power ground IN TRANSFORMER BOXES -2 & was delivering STRAY VOLTAGE extenal waterlines. Shocking experience just to wash your car.
With your long list of issues a survey of the electrical system will be needed to find the problem. Why hasn’t the HOA hired a professional to investigate?