If you are writing a dissertation then at some point you are going to need a citation manager. Since you are on macOS then BookEnds works flawlessly with Scrivener. (Zotero has issues.) You can gradually add your references that you use in your dissertation to BookEnds. This will allow you to add citations as well as generating a bibliography of all cited works at the end of your paper. BookEnds allows you to use a myriad of styles including but not limited to Chicago, APA, and MLA.
BookEnds has a lot of other useful features for writing a paper that Excel doesn’t have. BookEnds is specifically designed as an academic tool for the kind of work you are doing; Excel, with all its virtues, was not.
The following thread has a lot of discussion on the topic of citation managers that play well with Scrivener. You might be profited by reading it before starting your dissertation