I ran the Disks format process, @vasileios. Disks sees the SD card; Files does not. I have installed GParted if the problem is no boot sector. But I’ll need guidance on how to use it, sizes, format-types, etc. Total newbie, here!
Post-DOS format process:
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What Files sees… no SD card:
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Here’s what GParted sees:
Sorry to keep asking. And thank you for your help.
No worries @nwarren!
Thank you for sending the images! From the image below, click on the designated icon, while you have your SD Card highlighted and select Format & send me a screenshot of the window that pops up. 
First, select the green bar above that says “Free Space.” Then, the options should become available.
Ah! Format option available, @vasileios. Buuuuut, the options are all the same 3 as I posted earlier.
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Update:
I closed/re-opened Disks, clicked on “SD Card Reader,” then again on the large partition, then on the gear. ALL OPTIONS GREYED OUT AGAIN!!
How weird.
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Update 2:
There are 3, vertically-placed dots at the top, right of the Disks window.
I clicked there, and found THIS!
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So I am able to format. Although only the same 3 options remain available, as before, MBR/DOS being one of them:
It will work with those options, yes. Though, if you want to be truly Linux only, then I’ll need to know its device name, which lies under the big green bar. In that scenario, you can hit the terminal and give it the exact filesystem you like.
But still, the DOS (figure of speech, DOS), will work.
Here’s the result of my 2nd SD card format attempt, using Disks, @vasileios. Nothing changed. Files still doesn’t see it, and it doesn’t mount to my desktop.
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Ok, I’m taking this as a sign from the Universe. 
Please guide me thru the steps (Bash commands?) for obtaining the SD card’s device name in order to get the card read/write-able in Linux only.
Thanks…
@vasileios, via Terminal, I found the device, but don’t know how to rename it. Here’s my attempt, with Bash’s response (Looks as if the filenames need extensions?):
Progress!
Hey @nwarren!
Perfect! The bash command to format your SD card with EXT4 is:
sudo mkfs.ext4 /dev/mmcblk0
This should work normally. If not, please let me know. 
You cannot rename the device itself, only to assign a Label to it. This can be done in Gnome Disks you ran earlier - when you hit on the gear under the big bar to the right and select the FileSystem option (I’m on a different system and I don’t have Disks available now… first time in a while - go figure!).
@vasileios, you are amazing! In the process of setting up TimeShift, I came to the Home Directory option, no where else suggested why one should include Home, I should’ve searched for answers here first! 
But I suppose I don’t need to include Home for root?
Hey @Ai!
Root home is only required in case you run a distro like Kali, where the system logs you in as root to begin with - and the entire home directory structure is populated.
As for your own Home folder, make sure you have enough space on your target area, as the backup GB can accummulate.
Unless the drive you’re backing up to is BTRFS formatted, which makes it more economic.
@vasileios, thank you for explaining. And for timeshift I have it going to a drive larger than the one holding my Linux, so I am all set for backup!
Much appreciation!
One more question about TimeShift… Was I thinking correctly that if I want to backup onto an external drive, I can’t use BTRFS?
You can use BTRFS normally on any drive. In fact, I have a couple of RAID systems that do that.
Another option that has saved me several times is Clonezilla. I love this app! once I have everything set up, installed and tweeked I clone the machine. If / when I do something that I cant fix Clonezilla is my go to. I highly recommend it.
That is great to hear! Thank you so much for the info @waynetb!
Lately I’ve been “playing” around with OpenSUSE Tumbleweed, which I’ve installed on a Surface Laptop 3 and a MacBook Air (where I’m writing from). It’s definitely more challenging than most distros, but the lessons I learned apply to all flavors out there.
At some point, I’ll have to prepare a unified cloud solution - as I find myself working on many, different devices.
Totally agree. It would be nice to have all your data available no matter which device you are on.
