Synology NAS Refresh

[EVS]

I am using an old SYNOLOGY 4 bays DS411j with 8 Tb of storage. The system is configured in RAID 0 and all content is backed/synchronised nightly on a 8Tb USB drive using Hyper Backup. The system is for home use with only one user accessing the NAS from different devices.
I would like to upgrade to a newer Synology NAS probably with 2 or 4 bays with 30 Tb in a JBOD configuration and also nightly backups to USB drives. The device will be used to store files and possibly running a few docker applications. Could I start by purchasing a NAS with one large HDU drive and then add further drives without loosing existing data?
Can I also use non NAS drives?
I used to have a RAID 5 configuration, but as I have frequent backups and I can afford the downtime to replace a faulty drive from the backup, is it still advisable to use JBOD or RAID 0 to maximise the disk usage?

[ed]

With JBOD only the broken drive will loos data. With RAID0 all data will be lost. Technically it is faster to recover from JBOD. But RAID0 offers better performance sine the data is written and read from multiple drives simultaneously. JBOD writes/reads only from a single drive.
You will need plus series type of NAS such as ds920+/ ds420+ to be able to run docker and have better backup apps.
Migrating drives are also easy to a newer NAS.

I hope this helps.