Yes, as above, just deleting the folder isn’t a clean uninstall option and generally causes issue with the uninstaller. In some cases with AV in particular you have to install and uninstaller, but don’t know that to be the case with Avast, per se. I would re-install the product and then use the included uninstaller to remove it, if there is one.
https://forums.tomsguide.com/threads/solved-avast-is-impossible-to-uninstall-solved.443038/