How is a game I haven’t purchased on my home screen?
The Nintendo Switch Online account comes with some free DLC for Super Smash Bros.
When you choose to redeem this offer (or redownload it) it puts a shortcut to the actual game on the home screen. It also downloads data that consumes 1.8 GB of storage which according to the software settings is mostly a game update but 0.2 MB is the actual DLC.
I’ve managed to remove it by going into options and deleting the software, like you would for any other software.