NOTHING is safe. And Blizzard owns everything, so it’s not “your” stuff, they are under no obligation to fix anything, ever.
Just look at this: [Guild Bank Missing Items Bug – Aug/Sept 2024 - Support / Bug Report - World of Warcraft Forums] Guild Bank Missing Items Bug -- Aug/Sept 2024 (Part 1)
Tons and tons of stuff, wiped out, and barely anything done about it. They barely even TALKED about it, didn’t even acknowledge it until a month+ later.
So yes, you can expect that any of your goals or collections can be reset at ANY time, and all you can do is keep paying them to try and regrind it.