Dropbox update has caused Windows File Explorer to slow so badly I cannot work

Ever since this update was forced upon us, my File Explorer no longer works properly. It takes forever to load with a green bar at the top and white icons. When it does finally load, if I click on a file to either open it or copy it or whatever, I get the blue donut and nothing happens for ages. I have to go away and do something else for 5 or 10 minutes before it will finally allow me to right-click or open it. I am beyond frustrated now. It took me over an hour to complete a simple copy and paste task this morning that would normally take less than 5 minutes. I simply cannot run my business this way.

I've tried various things such as the obvious rebooting etc. I also tried to rename the Shell Icon Overlays as there is apparently a limit in Windows and Dropbox was apparently causing an overlay limit conflict. I also cleared my thumbnail/icon cache. Nothing I do is working. It's awful and I hate the change. I just want it to work. File Explorer isn't great at the best of times as it's so unreliable and I've always had to restart it 2 or 3 times a day. But now it's not working for me at all.

Please can someone help? I am incredibly busy at work and have now wasted a good 4 hours on this. I really desperately need to get on with my work. I'm using Windows 10 Pro and it's up to date.