You really should take a step back and relax. I'm going to tell you again, but will probably fall on deaf ears.. I'm not being impolite or angry just because you don't like what I have to say.
You say that you've 'spent months' reading about other storage on 'endless forums'..
Yet you have not picked up on the fact that 5-10 GB of other storage is perfectly normal?
You can ask what it is until you're blue in the face, you're not going to get a definitive answer unless maybe you go get a software engineering job at Apple. Then you can come back here and tell us what this is made up of.
You've compared your situation with others saying 'clearly other people are having the same [issue]', but you are in a completely different ball park. TonyCollinet and I are on this site regularly helping people with their iPhone issues. People that come here with legit other storage issues, it takes up half their phone. Often times it seems like it has to do with iCloud.
You've posted several screenshots of your other storage, I can quickly and easily measure with a scale and approximate that your other storage is below 5 GB. So as you've been told, there is nothing wrong. Your phone is acting normal.
You might find my comment of you obsessing over this offensive.. it's not my intent, but it is what you're doing. Have you actually tried to simply enjoy your phone rather than account for every 0.2 GB your storage number changes by? I have my doubts because you've also posted that you 'want to scream' after a slight increase in storage.. Just because you can't account for each MB of it. You 'don't have any apps', you delete all your videos and pictures.. Why???
You think your phone is going to sink with a slow leak.. Why? Has it happened to you before? Or just cause you read it's happened to others?
If I'm wrong about you obsessing about it, then prove it. Don't look at your storage capacity for 1 month and just use/enjoy your phone. Can you do it?
I've owned various iPhone models for about 10 years now. It has been years since I've restored my phone because of any storage issues.
Since you started posting, I actually started checking my other storage as well. I don't really care what it does until it gets crazy..
Well of course every time you post it would remind me and I'd check my storage again.
MY storage was being a bit unruly. It had climbed up to ~16 GB. So I was kind of chuckling to myself that I was telling someone else not to worry about other storage while mine was elevated. So I monitored it since my initial response to you (just over a week ago) and it's been plateaued the whole time. 15-16 GB the entire last week. It has not continued to climb. No slow leak, no sinking ship.
One thing that I did discover, I compared my iPad storage to my iPhone storage and noticed that the Pocket Earth app was not listed on my iPhone near the top of the storage consumers. But I KNOW that it should be because I always download an offline map of the USA that's around 8 GB in size just in case I need it. So I opened the app and verified that the offline map was still on my phone.. it was. I then went back to iPhone storage and gave it a minute.. what do you know? my other storage dropped down to 7.25 GB (which is now perfectly normal).
So who knows what the reason behind the misrepresentation was.. The app hadn't been opened for awhile and iOS didn't know how to classify the data? The app is supposed to report what the data is and didn't? The app had a glitch? iOS had a glitch? I'll never know. And that was just one app that I got lucky and noticed something seemed off. Had I not figured this out by mere curiosity, my phone still would have been just fine. Are there other apps doing the same thing out of the ~300+ I have on my phone.. more than likely.