Honestly sounds like you have an issue with explorer and Win32 processes on your computer. If File Explorer is crashing when you press browse that's not our code running and is native Windows calls. If you haven't already make sure to run command prompt as admin and run "DISM.exe /Online /Cleanup-Image /RestoreHealth" (without the quotes) first and let it run. This ensure Windows has the latest and correct definitions for what files your OS should be using. Then run "sfc /scannow" (again, without the quotes) and let it run and see if it corrects anything. If it does restart your computer.
File explorer and those Win32 processes also REALLY lag behind if you have network locations not actually hooked in and communicating properly. I have a network drive that is often off and Windows still tries to ping the thing when File Explorer first opens and it causes issues and extreme delays at times in my own File Explorer processes across several apps (and even Windows itself). Sometimes you can alleviate the issues with it doing so by opening File Explorer in windows FIRST, and THEN doing it in the app. I believe it has a sort of response cache it'll utilize and causes it to happen far less often (or least does on my machine).
Also some of what you're doing is still WAY more work than you'd need to do even if you can't run File Explorer via LB. For example import the game (can do multiple by just drag/dropping files from File Explorer to LaunchBox) and then in the import options check the box that says something like "Use Folder Name for Game Name" should help if the exe is some random filename. If it doesn't rename the title and then in the edit game window immediately press "Search for Metadata" and then pick the game from the drop down. Then you can go to the Images or Video tab and grab images for it from there, or when you're done doing that for all the games you are imported just run the Download Metadata/Media wizard. If THAT doesn't find the images you need and you have to manually grab them, instead of manually moving/renaming them just open the Edit Game window for the game you're adding them to and then go to the Images tab and drag the files to the preview area. Now set the Image Type for those images that you added and save the Window. We'll copy the images to where they need to go and name them correctly for you.