Syncjob takes forever

Nextcloud cron is taking forever, and what I have noticed is that the SyncJob and PreviewEnhancementProcessingJob are the main issues.

When there are many users, these jobs take several hours to run. What is their actual purpose? Are they essential, or can they be removed from the cron script?

Steps to reproduce

/usr/bin/php -f cron.php

Expected behavior

Slow

Nextcloud Server version

30

Added a github issue for this as well : syncjob PreviewEnhancementProcessingJob taking forever · Issue #50811 · nextcloud/server · GitHub