Unable to update software

9GBs available of free storage? Gotcha!

So, using this article, Locate backups of your iPhone, iPad, and iPod touch - Apple Support, see if you can confirm if you have a recent backup. If not, see if you can backup to iCloud via Settings > Your Name > iCloud > Backups & select Backup Now. Once the up-to-date backup time/date is confirmed, I would try doing that Recovery Mode Restore via If you can't update or restore your iPhone, iPad, or iPod touch - Apple Support (ignore title).

After that's finished, restore that iCloud backup when going through the setup assistant. It should also help to clear up 'other' and 'system' storage while updating the device to iOS 13.6 fully.

You can definitely backup to iTunes if you so choose. Personally and this is all personal preference. . .

I prefer iCloud backups as they’re encrypted, aren't a ‘hard copy’ meaning if there’s a corrupt or damaged file, it isn’t saved within that backup like an iTunes backup would save those files. It’ll also help to eliminate other/system high storage amounts.

You could try going to • Settings > Your Name > iCloud > Manage Storage and removing some things from the backup to make it smaller or delete an old iCloud backup that’s appearing to make room for an up-to-date one. Plus, purchase an upgrade the iCloud Storage if you so choose.

-- About encrypted backups on your iPhone, iPad, or iPod touch - Apple Support

I definitely would suggest looking at the iCloud backup option in the future if possible as it's very easy, auto-encrypted, etc.

As far as backing up your device goes, I would follow this article with the steps directly. :) -- How to back up your iPhone, iPad, and iPod touch - Apple Support

Settings > General > iPhone Storage. How much available storage do you have?

Do you have a recent iTunes or iCloud backup? If so, did you try doing a Recovery Mode Restore via iTunes using HT201263. It will wipe all the data, download the most recent version of iOS, then install. If you have a backup, you can then restore that data afterwards.

Let me know :)