OneDrive Files slow to load when opening from Excel/Word.

Hi, sorry everyone, the notification e-mails for replies were going to my junk folder...  We are using OneDrive for Business.

So what's happening is when the user is in Excel/Word, and they do a Open, then are presented with a list of default locations they can open from.  e.g. Recent, Shared with Me, OneDrive, This PC, Add a Place, Browse.  This user is selecting Browse, which then opens up a file explorer view window and she then clicks on the OneDrive - OrgName folder on the left-hand side.  Once clicked, the files and folders stagger as they update and after 20-30 seconds it fully populates. 

She's a heavy OneDrive user so there's probably 100 folders in the root of the drive and 200 files on the root as well.  Each subfolder has files in as well.  When I try this under my own account, I have around 10 folders and 5 files at the root of my OneDrive folder and it still staggers, but only takes a second or two to fully populate everything. 

Both her and I are on the same network in the same building. I'm actually on WiFi, but she is hardwired at 1Gbps link.  She avoids the web method of OneDrive as relies on the local copy of the files on the hard drive.  Would WebDAV still be a factor if using the File Explorer (browse) method?

Hope that all makes sense.  I appreciate the replies so far.