Did you actually try to check for your dates on the Hilton site / app? That would be the easiest way to verify initially.

Now at the moment it seems no rates / inventory has been loaded yet for Jun 2024 for that property. Similar for Hilton Sorrento (Italy) near Amalfi coast. Also some Japanese properties like Conrad Osaka may not load rates 11-12 months out, but much later only.

I can't tell you when they will appear, but personally, if I'm looking to secure a room at a property that is not showing availability yet, I check at least once a week to see if anything has come up. Additionally, at times, the first batch of rates loaded far out may be close to rack rates or initially inflated and later moderate in price, but no one can guarantee that of course.

Usually, I book a flexible rate to lock in a room / suite and then monitor and rebook as needed / possible if rates drop. Everyone has their own strategy. YMMV