Memory and iTunes problems ("iTunes could not back up the iPhone because the iPhone disconnected")
I have an 16gb iPhone 5c, and the problem I usually have is that most of my available space gets filled with the "Others" category (right now that is more than 7gb). Normally, I would make an iTunes backup and then restore my phone with the backup, so that the Others category would go down to a minimum. Now the problem is that iTunes won't ever complete the backup ("iTunes could not back up the iPhone because the iPhone disconnected") and, therefore, I can't restore my phone to have more space available.
I've tried changing the cable, using different USB ports, different computers (with no backups saved from before), updating iTunes, having Airplane mode on while making the backup, restoring the settings... Nothing works for me. I've read about DFU but I don't really understand how to fix my problem with that method. Would it erase everything that I have on my phone that isn't backed up? Because I really want to avoid that. What about recovery mode?
I have iOS 10.3.3 (lastest available according to iTunes), so my phone isn't exactly the fastest and most efficient, but with the lack of space it gets so much worse. It's starting to bug constantly, and I need to find a way to at least get iTunes to complete the backup.
Any advice/solution? Thanks in advance.
iPhone 5c, iOS 10