Raid together fit
I have an iMac 27" 2019 and I'm getting a new external hard drive. My question is Can I connect an external RAID hard drive to my iMac?
iMac 27″, macOS 13.5
Yes you can connect most any external drive to your 2019 iMac.
The type of external drive, really depends on what you want to do with the external drive.
(Time Machine backups, extra Storage space, as a Startup disk, for a Clone backups)
For example:
A large external HDD is all you really need for doing your Time Machine backups.
A large external HDD is all you really need for added external Storage space.
A decent sized SSD is all you really need for an external Startup drive.
A decent sized SSD is all you really need for making Clone backups.
I personally do not and will not ever rely on just one single external drive enclosure or a raid external drive enclosure. What I do is use multiple external drives. One external HDD for Time Machine and two external SSDs for Clone backups using CarbonCopyCloner. The Time Machine backup drive stays connected to my Mac 24-7 and the Clones get updated daily and weekly.