Android e6 Storage Permissions Madness!

PHONE INFO:
Moto e6 (XT2005DL)
Android ver: 9
Build: PPBS29.73-81-5-14-5-4
Kernel: 4.9.112-perf+
Carrier: Simple Mobile
Using almost entirely stock configuration
__________________________

Hi everyone (and thanks!),
I have a cheap Moto e6 through Simple Mobile and it's totally great except for this one issue.
It has limited internal storage, but a terrific SD card expansion. I'm having three storage-related issues, and solving any one would probably be enough to solve my overall internal storage issue:

> I cannot access the SD card through an application manager except in read-only (I'm assuming, by the behavior)
~ Several file managers will allow me to view internal storage and "move" items to SD, but while no error is produced, the move does not happen.
* Adding "storage" permissions to the various file managers doesn't seem to help
> I cannot access the internal phone memory when plugged into a computer (SD only)
~ I turned on developer mode
~ I turned on debug mode
* No change
> I cannot move some applications from internal storage to the SD
~ A handful move just fine
~ This is not limited to stock apps, it includes various things from the app store
NOTE: moving apps OR images/video/music would be enough, I think. So don't feel like you have to tackle all this. And I'm down to move it via phone, PC or Linux and am entirely comfortable behind a command line if need-be.

I also was considering granting a file manager temporary administrative permission to the phone, but these options are greyed out (I assume I need root for this?)

In my exasperation I attempted to root the phone but none of the mainstream methods I've used in the past worked in this case (not too surprised on such a niche device). Rooting the phone is an entirely valid approach if you have a suggestion for the e6. I don't care about warranties, the phone was literally $25 and if your suggestion breaks it I won't hold it against you.

Really I'm open to anything. I've got <1GB internal available and essentially limitless available on the SD card. I'm almost ready to email myself all my pictures in batches so I can move them that way.

 

Hey folks! Thank you so much and I'm terribly sorry for the delayed reply. My car broke down and honestly it's been taking all my attention. But all's well that ends well!
You're absolutely right, that is how I configured my SD card. It's important that I have my SD encrypted because I use my phone in HIPAA contexts. I avoid having protected information on my phone, but I don't take chances. I had just sort of assumed that the SD would be mounted through the phone somehow but retrospectively that was pretty presumptuous.

I think your answer does answer the original question as presented, because I could simply reformat--but is there a solution that doesn't involve leaving the SD unencrypted?

Regarding the cloud based solution, it also answers the question as asked. I avoid cloud sync for the same reason I'm not wild about unencrypting my SD, but it's not like my photos contain HIPAA data...so maybe that would work. If nobody has any local solutions, I'll look into that.