RAID type for 12x 10TB drives

What is the best RAID type for a 12-bay Synology NAS with 12x 10TB drives? At the moment, it’s configured as RAID5. I’m thinking of RAID6 – but is RAID6 recommendet for such large drives? How big is the risk of URE? What about rebuild times?
The NAS will be used as backup repository for Veeam.