Both Microsoft Word itself and inserting a citation are laggy! Honestly, it’s the doc itself that’s more annoying. It takes forever to type a sentence and edit! The typing lags quite a bit. All other apps run fine! Thank you for any thoughts :))))

But is a new, empty document also slow?

If it's only happening in a large document, you'd want to disable automatic citation updates to improve the speed of Zotero citation inserts, but if just interacting with the document itself is laggy, that's a Word issue, not a Zotero one. It's not impossible that a Zotero citation — or, more specifically, some of the embedded item metadata in a Zotero citation — could trigger slow performance in Word, but Zotero itself isn't involved at all when you're just interacting with the document. You're purely interacting with Word.

In any case, you could still follow the last step on Troubleshooting Errors in Word Processor Documents, which is a generic process for quickly cutting down a document to find a section that's causing trouble, whatever the cause. (If it's a cumulative effect from the size of the document, though, you might just find that the smaller the document the faster it is.)

Also, if you have any other Word add-ins, you should try disabling those. The Zotero plugin only runs when you click one of its buttons, but there are other Word add-ins that do run at other times.