426.3MB World Won't Upload to Realms

My survival world is exactly 426.4MB large. I try to replace a world slot on my realm with my survival world. I try multiple time and always says error regardless of strong internet connection or not. My ps5 is 3 months old at the time of this post so that might not be the issue. Upload size also shows as 354.5MB instead of my world size of 426.4MB.

STEPS: (repeatedly by the user of the game and console)

1. In the ‘Worlds’ tab, select the pencil edit icon in the right side of your world you want to upload on Realms.

2. Select ‘Play on Realm' in the left side. Choose the realm server, then the world slot to replace.

3. Import world progress bar will show up. It may or may not fail or be successful. If successful, the upload progress bar will show how many MB are uploaded out of the the full size of the world you

Expected result: World was successfully upload and replaced original world slot.

Actual result (repeatedly): An error occurred.

READ: Attachments NOT in order.They are backwards. My world size at 426.4MB is first, exporting world starts sometimes there's an error, but when successful, upload starts then says error occurred near the end of upload multiple times. Uploading small Worlds however works just fine.