After doing a sys-upgrade to 19.07.4 from 19.07.3, LuCI broke so I decided I'd just do a factory reset and restore my backup to hopefully fix my issues. I factory reset, restore my image, but I am unable to connect to the internet. My guess is that my DNS is broken because in the past I used a package something like dns-over-https which isn't in the repos anymore or changed it's name. How do I restore my previous backup and get my router to connect to the internet?
Maybe the best bet would be to download the packages manually and then install them? How would I go about doing this?
Well, you revert the factory reset by restoring the faulty config...
You always need to reinstall add-on packages after sysupgrade (unless you compile a personal image with all needed packages).
Either reconfig manually (without restoring config), or install the missing packages.
Easiest might be to install packages while you use the default configuration, so that you have connectivity. (Having a modified DNS config without the needed packages is a sure way to break connectivity)