After uploading a file it takes up to 20 minutes until windows can sync it

After I upload a new picture with my Phone it takes up to 20 minutes until the windows nextcloud client can synchronize it. Is there a way I can speed up this? I always get the error that the file was deleted on server and could not be located.

Windows Sync Log

#=#=#=#=# Propagation starts 2023-05-28T09:44:55Z (last step: 617 msec, total: 617 msec)
||Bilder/Timeline/Handy/Bilder/2023/05/PXL_20230528_094012433.jpg|8|2|1685266815|5bd150b157ddb0ceed68c31d6f5e6f5a|2648192|00910074ocay84hyywl0|2|File was deleted from server (File with name /Bilder/Timeline/Handy/Bilder/2023/05/PXL_20230528_094012433.jpg could not be located)|404|0|0|600b3de0-9fc2-4605-b0e5-7eb4a660680a|

My system has about 25000 files with 91~GB. My proxmox container is mostly sleeping.