I'm one of those people who actually learned about computers instead of blindly relying on third-party software to do everything for me.

This was during the time when compiling every app yourself (./configure, make, make install) was the best bet for a clean computer system and using Terminal for hours was a daily requirement. I spent 10 years using nothing other than GNU/Linux and BSD as my sole operating systems on several home and work computers. We don't need 'cleaning' apps on macOS, you can take care of this type of thing yourself and you'll be much better off. The point is that you won't have an app 'guessing' and possibly trashing something. The advantage of doing it manually that you can research every file/folder before deleting it - or you can move them to external storage or whatever you want to do. This stuff is almost always going to be inside the ~/Library, and possibly iCloud Drive, folder and it's the same thing app cleaner software does anyway - finds and removes stragglers. Then, use the search function in the Finder toolbar to search the Library for the app name and/or manufacturer name and you should be able to find all traces of the files left behind when deleting an app.

Open Finder and go to the Library folder in your Home folder. Click to expand.This is why I always tell people to learn how their Mac works and learn about the folder structure.

Mac app cleaner