Me again....
The old proverb “buy cheap, buy twice” comes to mind. I’d suggest that the OP gets replacement fasteners from somewhere like Pro Bolt - more expensive than FleaBay, but what’s the cost of three hours of time and frustration? I’d also recommend avoiding aluminium fasteners (anodised tat is just SOOO mid-90s doncha know?) - get stainless or plated steel and use that smear of Copaslip on the threads.