Nanatjits you needed to carry out a network transfer from your previous console. If you still have it follow these steps:
On the Xbox you want to copy from, press the Xbox button on the controller to open the guide.
Go to Profile & system > Settings > System > Back up & transfer > Network transfer and check the Allow network transfer box. This makes that Xbox visible to other consoles on the same network.
Once you’ve allowed transferring from the “host” Xbox, turn on the console onto which you’ll be copying games and apps, and go to the same settings page. Your host Xbox should be listed.
Select the Xbox you want to copy from, choose the items to copy, then select Copy selected.
If you have any problems here's a link to Xbox Support:
https://support.xbox.com/en-GB/help/hardware-network/getting-started-set-up/move-from-xbox-one-to-xbox-series-x-s
There's a Live Chat option there to speak to them directly if you still can't access your packs, since they were purchased from Xbox. Good luck.