This depends on if you purchased the Ultimate Edition or just the Next Gen edition. If you only purchased the Standard Edition for your Xbox Series X you won't be able to install the game on your Xbox One, you would need to buy the game again.
This depends on if you purchased the Ultimate Edition or just the Next Gen edition. If you only purchased the Standard Edition for your Xbox Series X you won't be able to install the game on your Xbox One, you would need to buy the game again.