Your labelling system is a good idea! I do have plenty of games from bundles, but I only add the ones to my library that I’m actually interested in. So everything in my backlog is something I want to play at some point. Personally I don’t feel that there is any negative connotation to the word backlog, but maybe that’s because mine is full of stuff I intend to play.
I have a spreadsheet listing the games I’ve got to play, and whilst I do usually set an ‘up next’, this can change depending on how I’m feeling at the time. So it’s rare that I play a game I don’t like or doesn’t fit my mood :)