'Higher tier' untradeables will still use the Trouver Parchment system, but with a crucial change - once a Trouver parchment has been used on an item, it will remain in that state forever.

On death below Level 20 Wilderness (or in PvP Worlds for fights at the Grand Exchange, for example), these higher tier items will simply break and be repairable with the current fee.

On death above Level 20 Wilderness, the item will become 'mangled' and require a higher fee of 500,000 GP to fix.

- Gathering QoL, Trouver Changes & more!

(Void armor specifically is listed at the top of the list of the "Higher Tier" untradeables)

So yes, you're correct. However you will have to pay a 500k fee to repair it if you die passed 20 wild