Ticketmaster are shockingly bad, yep. 😅
I flicked DE's events person a message when it happened saying it looked like the URL had been leaked internally, in all likelihood it was just insider knowledge/educated guesses as you say. I'd hope with it being raised it's something they keep in mind for 2025 - it's also very late for those of us overseas when we need to book international flights and their prices go up. They're non-refundable so you need to have the event ticket secured to know you're actually going first.
Oh and your steps taken prior to purchase is relatable - 11am EST is 4am Good Friday for those of us in NZ, so we'd set alarms to get up early and I'd actually gone to the extent of entering my payment information on the Warframe storefront and talking to my bank to green flag their merchant service so a large sum purchase at 4am on a public holiday didn't trigger fraud alarm bells. Little did I know it wasn't even being handled by them and would just be an Eventbrite thing. 🤦