What phone are you using? If you are using the stock "Files by Google" app as your file manager, it should show "Recents," but also below "Recents" it should show "Categories," "Collections" and "Storage Devices." "Storage Devices" can be tapped to open up all of the files on your device. If "Files by Google" is your file manger, you may have to clear its cache and storage and restart your phone to get all of the files to show properly.
Long press on the file manager app icon, tap App Info, tap Storage and cache, tap Clear storage and tap Clear cache, restart your device. Note that when you clear Storage, you will lose any files you may have placed in Safe Folder, anything you may have Starred and any Settings you may have set for the app (you do not lose any of your files).