We should create isolate "virtual environments" in Anaconda (and "pip") to avoid tinkering with the "base" one. I have a few; one is devoted to homework related packages and I'd rather not touch it. In the future you could experiment with that feature to ward against undesired updates, changes.
As for your issue, Windows logs might shed some insight. Run Spyder from an Anaconda prompt, by typing its name, watch it hang. Search for "Event Viewer" in the Start menu, then select "Windows Logs", then "Application" and look for "Errors" and their description. You can then Google the reported exception code and module (likely "python38.dll"). Don't get your hopes high but there might be existing resolved bug reports. Given that you also have issues with Navigator it may be a QT related problem, possibly with PySide (Python's QT bindings).
I remember Anaconda being a pain in the ''.join(('a', 's'*2)) while removing it. There's a package one needs to install, which cleans up caches, lock files, tarballs, etc. — it must be run before uninstalling the whole shebang. Check out anaconda-clean. Best of luck!