My Win 11 file explorer mostly works fine. It's the initial directory you open at. When you first start file explorer or open a folder or folder shortcut its fine. Browse the dir tree and its fine forwards, back works fine unitil you return all the way back to the initial folder you opened, then there is a pause of about 6 seconds. Occasionally it even says Not Responding in the title bar. Eventually it comes back to normal.
I also noticed a similar problem in 3DS Max. When I go to load a bitmap in the material editor and the file explorer window starts, there is a similarly long pause.
I removed One Drive and Teams from my system early on, as well as disabled recent files because I heard that the new File Explorer searches those when you initialize a new instance. That didn't help.
I tried the F11 full screen Win 10 File Explorer trick and that works. That isn't very productive when you need multiple windows and apps open, and certainly doesn't help 3ds.
UPDATE:
I looked into the Disable Explorer Command Bar.reg posted before*.* There was both disable and enable reg keys in the zip file, so I tried it and it works.
It also fixed the 6 second delay in the 3ds Max material editor when I am browsing for and assigning a new bitmap to a material.