I experimented this week with oil drop photos. I added cooking oil to water in a glass baking pan, then illuminated and took shots with macro lens. For some of the later shots, I added a little detergent. For some shots, I put colored construction paper under the dish. Later, in post, I sometimes added color graduated filters as Photoshop layers and blended them in various modes. The "lights" on some of the spheres are reflections from an LED macro ring light. The results seem sort of other-worldly, and/or psychedelic.

My Backblaze cloud storage subscription expires on 4 October
I am thinking that there may be other alternatives that are more attractive and poentially offer more benefits
specifically for photographers

I do not store any documents and have decided not to store jpeg images in the cloud; keeping them on primary and backup external hard drives

Specifically, I require the following
RAW file storage
Unlimited storage
Ease of use (I'm "tech" deprived)

Attributes are more important than price (within reason)

Any suggestions from this great goup would be most appreciated

THANK YOU

You can pick up a second monitor fairly inexpensively. Using a second iMac as a display only is a waste of a machine. An old Mac is better used as a simple file server and/or a place to backup or off-load files. It can also be used for email, web surfing, or other tasks while your "newer faster" computer is doing the heavy lifting with LR and PS. It can also be a backup system. Used as a monitor only, you cannot easily update software or sync files.

Again, I'd still like to see what bpulv meant by the comment and what benefits are perceived from that setup.

Yes, I'm aware of those methods. I've run my Macs with two or three monitor setups for years. What bpulv wrote was two 27" iMacs that are cabled together - not two monitors. Considering the detailed post, it seems it was meant as written.

As chasgroh pointed out, there would be lag if running a two-computer setup. Even if connected by a direct network. Such a setup would also create issues when trying to send a file directly from Lightroom on one machine to Photoshop on the second - I'm not even sure LR/PS can roundtrip over a network connection.

That's why I asked bpulv for clarification. If it is the two-computer setup as written, I am curious what benefit is obtained in this photography workflow over a more tradition two-monitor setup.