I own an LG V20, and sadly...That is The LAST Flagship phone that will be made with a removable battery. Manufacturers have learned from Apple, that creating phones with removable batteries decrease their phone sales and profits, because consumers tend to keep their old phones longer if they can simply replace the battery when it goes bad as opposed to buying a new phone.
The current issues you're experiencing with updating your phone software are THE EXACT Reason why I NEVER do any phone updates. I will occasionally update my phone app software, but I NEVER update my phone's Operational Software. Because updates almost always cause some type of aggravating technical issue.
My advice to you; purchase a Verizon Unlocked LG V20 (Great Phone!!) at Amazon.com for $349, and NEVER do another OS Upate....Again!! Android 7.0/Nougat works perfectly. I've been using mine for years now with No: Malware, Hacking or any other issues....Hope This Helps..