I'm able to solve this issue with 100% success rate by doing the following on an XBox Series X:
Initiate download of new content
Wait for the "Importing Content" message to appear
Progress bar will be stuck at 0%
Press the XBox button on the controller
Go to your XBox system settings from the overlay menu
Exit the XBox system settings once loaded
The red Mojang logo should appear, followed by a quick loading bar while Minecraft loads back into memory
The "Importing Content" screen should appear again
The progress bar will start to move right away towards 100% and will complete within seconds
I hope this helps in debugging the cause, or at the very least, serves as a work around for others.
Cidan
I'm able to solve this issue with 100% success rate by doing the following on an XBox Series X:
Initiate download of new content
Wait for the "Importing Content" message to appear
Progress bar will be stuck at 0%
Press the XBox button on the controller
Go to your XBox system settings from the overlay menu
Exit the XBox system settings once loaded
The red Mojang logo should appear, followed by a quick loading bar while Minecraft loads back into memory
The "Importing Content" screen should appear again
The progress bar will start to move right away towards 100% and will complete within seconds
I hope this helps in debugging the cause, or at the very least, serves as a work around for others.