A new item available through either the wildercrate or the coin shop (maybe the ruby crate) that is a special totem of undying that can save you from a void death. I think to be balanced it would require some sort of additional sacrifice, like a netherite ingot has to be in your inventory for it to consume or something. It could also function ONLY as a void save, so any other death (say falling or slamming into a wall) would not be stopped by this totem. The way it saves you would be to place you on a small (3x3?) platform of end stone or something as low as possible above where you fell. This could be difficult to implement but is something I imagine there'd be lots of interest in.

Personally, I don't think there's anything of equivalent value to preventing a completely normal vanilla death mechanic. This just feels like "if you have the cost in your inventory, you can't die."

But if you did get it implemented, I'd say it'd be easiest to say "if you take damage from the void and drop below 5 HP, you get instantly teleported to local spawn".
It'd be like a false restart. I use the 5HP mark because the void does 4HP per tick, so it triggers before you die, and you're put into a safe place. You can PROBABLY get back decently quick as well since there's end portals at spawn, but this removes any odd logic needed to make a platform or something like you mentioned. Maybe not as snazzy, but hopefully far easier to implement.