This is very unlikely to happen for a variety of reasons. Mostly because in order for UW to send updates to Subnautica on consoles, they have to go through certification with Microsoft. Including experimental versions on the console would also require more time to program separate versions into the game, taking time away from developing the current playable version.
Right, what TwigRTS says. Everytime we do a new update on Xbox, we need to send it to Microsoft for certification. With the experimental builds on PC we are sometimes updating the game multiple times a day, so it is unfortunately not feasible to carry over the experimental builds to Xbox.
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if the game is finished, there is no point of having the experimental mode
Take a look here if you want to see what they're up to now. If that isn't multi-tasking I don't know what is!
And as @Trollolol07 says, why would you want one when the game is finished?