Do you have steam and standard accounts? If so, use a symbolic link to point the steam version to the PC version.
If you only have the one, then no duplication is necessary.
ESO is far larger than 38 Gb on its best day, and hasn't been considered Tamriel Unlimited for some time. Looks like you've got some artifacts going on.
Delete the files, then go into steam and try to launch ESO. Steam should download the updated version and you should be good from there. If it does not download directly, Right Click on the game, select Properties, Local Files, Verify integrity.
Your file structure under Zenimax should look something like this:
Just because you don't like the way something is doesn't necessarily make it wrong...
IRL'ing for a while for assorted reasons, in forum, and in game.
I am neither warm, nor fuzzy...
Probably has checkbox on Customer Service profile that say High Aggro, 99% immunity to BS