Upgrade possible from ESO Standard + Morrowind to Deluxe Edition on Xbox?

I own ESO on Xbox (and now PC thanks to Play Anywhere) as well as the expansions through Morrowind. I’m interested in upgrading to the Deluxe Edition to get all my missing packs, but the only option seems to be to just buy the full ESO Deluxe Edition. Is anyone aware of a better way to do this, or is the full Deluxe Edition my only option?