Is there any way to download parts of the engine and update the files; replacing, or adding them where needed, without reinstalling the entire 20+GB download required to update? If the answer is no, please explain why not and if there is any way around it. This could greatly reduce the internet usage. Thanks devs!
Less chances you find an engine dev here on answerhub, mostly this is community like you and me.
As far as I know there is no way with the launcher builds. It are completly seperated from version to version without an update/patch functionality. I would suggest you go with the source build from github, you can checkout a branch with the versionnumber and build it. If there is a new version, just checkout the new branch from git wich will pull only the deltas from the internet. Of course you need to rebuild which can take some time (depending on your machine)
I will try this, Thanks for your response!