External DVD/CD optical drive and external SSD storage drive recommendations for 2019/2020 iMac 27 please!

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I would not consider an iMac (Retina 5K, 27-inch, 2019/2020) obsolete at all. It is still fully supported, and the 2020 models are still sold new by Apple.

For the SuperDrive, I would recommend the Apple USB SuperDrive - Apple. It will work just fine with your Mac.

For external storage, if you don't need it to be "cutting edge fast", a good-quality external 7200-rpm desktop drive would work well, such as a SanDisk Professional G-DRIVE - Western Digital. If you really want a fast external SSD, a good choice is a G-Technology G-DRIVE mobile SSD R-Series Storage - Apple or a SanDisk Professional G-DRIVE SSD - Western Digital. Notice how much more storage you can get with a hard drive for a similar price, but again, the SSDs are much faster. It just depends what the drives are going to be used for. If you let us know, we can make even more specific recommendations.

Jack

An SSD is not always the best drive to be used for backups. It’s speed goes to waste and you want a really large drive for backups.

Another external SSD option that you might like is the LaCie Mobile SSD Secure USB-C Drive - Apple.

Jack

My Apple Super Drive works great connected directly to my 2019 27" iMac (do not use a hub). With the cost of SSD's dropping I have now gone that route for all my external drives as I like the speed as I move files back and forth and takes up less room on my desk.

From 2015 until later 2020, we used rather high capacity LaCie Hard Drives to backup. When we got new iMacs in late 2020, I decided to change our backup strategy based on our usage trends.

Our personal data history is backed up in multiple ways on multiple platforms: hard drives, iCloud for interactive access, Optical disks of archival quality and so forth. We thusly have no need for external hard drives that are 2-3 times the size of our internal disks ... same size is perfectly adequate. Internal drives contain current data that is periodically added to the historical archives. Those periodic additions also provides opportunity to determine continuing data integrity. Only sounds hard; takes very little time to maintain.

That being the case with our historical data as secure as humanly possible on various platforms, I opted for speed. We now have at least two SSDs per iMac to have both CCC and TimeMachine backup redundancy.

Not for everybody, and most certainly more expensive than platter type drives, but the solution has worked very well for us. Speed over capacity is a personal choice, We tried both and now we.'ve settled on SSDs. I always found the possibility of shutting down during a backup to be distasteful if not damaging. I just don't like to do it.

With CCC I have essentially more configurable TimeMachine-like backups that take place very quickly and have stop/start notifications. Purely a looks good, feels good solution but we prefer it. And considering how quickly TM adds data to and existing dataset, the likelihood of interrupting a backup to shut down is greatly lessened.