Are there any good sites or articles that detail the changes from og d2 to d2r?

Just a few QoL changes and more bugs. Go read the b.net patch notes for a detailed list.

Bnet patch notes will be able to best inform you. Not being mean but just saying there’s a lot of updates, some minimal, some bigger, so depending on your interests in the game, you may find some of the details more important/less important than others