Samsung Cloud: You can backup only 2500 Calls. Messages the same, older just get deleted.

WhatsApp: My backup is 7.9 GB big few months ago. Today I switched to the S23 Ultra, and Im missing around 2000 photos, the Backupsize is still 7.9 GB. No my drive storage is not full.

​

What is this? I always wanted to keep every chat and call I have, but its not possible because of this, anyone knows why?