(YOU WILL NEED A HACKED CONSOLE BUT IT'S NOT ILLEGAL SO YOU SHOULD DO IT ANYWAY {I use the aurora dashboard}) I bought the starter pack and the sonic level pack about a year ago and everyone online said it's impossible. I did it though. I just got the files online, put them in a usb drive and moved them to my xbox. I went into the file manager and went inside hdd1, then content, then 00000000000. Then I made a folder (FOR UPDATES IK THAT THERE'S ALREADY ONE BUT THAT'S FOR THE GAME DATA AND ONLY IF YOU HAVE THE DISC INSERTED) with Lego Dimensions' Title ID: 5752084B inside the 000000000 folder, and inside the folder made 2 folders, 000B0000 and 00000002. If you're using Aurora, then 000B0000 should say [Title Updates] next to it and 00000002 should say [Marketplace]. In 00000002, you'll need to put in dlc files (level packs and adventure worlds) but also Character and Tag Item Contents (1,2,3). In 000B0000 just put in title updates (the ones that begin with tu). Then restart Aurora. It should say backing up Lego Dimensions. Then go onto your game (don't launch it just hover over it) and click the Y button. Click on Title Updates, you should see your title updates' version, mine was version 23. Make sure it's enabled. Then go back but still hover over title updates. Move left with the joystick or D-pad to see the DLC. Go inside it and you should see the DLC packs you installed. If you do see both DLC installed and Title Updates enabled, then you can launch the game, play, and have fun with year 2 content. If you have any questions you can ask me in the comments.
Links I used:
Title Update 23: https://digiex.net/threads/lego-dimensions-tu23.16623/
DLC FILES: https://romsfun.com/download/lego-dimensions-3-48811 (This one might download an app called "download lego dimensions rom", don't use it, delete it permanently (It's not a virus but it's useless))
Have fun!