Finally! Apple released the macOS Big Sur 11.2 update. It seems to have fixed the Finder unresponsiveness issues. It is very snappy, everything seems to work nicely and quickly. Some Apps still have permissions issues, but I think that is on the App Developer. YMMV, but I say this might be a very helpful update to install. There is no Combo Updater, so you have to install from the Software Update panel.