LynnMarie Hi Lynn, I have the same setup as you and the same concerns, so I will point out to why I have chosen to run the way I do so you can then make your own mind to which way to run.
Just like yourself I don’t want to do unnecessary work and I want to keep things efficient and safe , because ST3 at the moment does not auto sync all the devices we are forced to do a full backup then transfer this full backup to another device to keep all devices up to date.
So what I have worked out is to use one device as your master device where you complete your backing tracks and do the main transfers to first, I chose my iPad as it can do basic audio editing and editing text and syncing lyrics is actually easier than using an iMac and as it’s also the device I use on stage it’s very safe as when things are completed you know it will be like that on the gig, but I then create a full backup of the iPad and transfer this to my iMac and the iPhone , I then know I have a safe backup at home in case my iPad gets stolen or dies, and I also have a full backup on my iPhone which travels with me to all gigs and acts as a backup incase iPad dies but I also use it as my background music player, this means I only use one device to create but 3 devices in total , I don’t rely on any iCloud’s all my stuff is on my devices my iMac has a backup system as well on an external drive so that’s my fourth backup so I am never worried about my precious music data that I have spent years developing.
I use a 256gb iPad a 512gb iPhone and iMac 512 ram drive with 5tb storage drive.
I find the 10.5 inch iPad is easier to work with than an iMac with a mouse.
I hope this helps.
Cheers Damir