>The issue is Defender in sync mode/other AV/other file system filters.

I've had folders take a full minute to open on an SSD.

It got to the point where I went to open the folder, it started loading. I needed the file quickly, so I searched for it online, found it, and opened it before windows finished loading that folder for me.

After exempting that folder from Windows Defender the folder loads instantly. For the life of me I cannot understand why Defender blocks Explorer.