@Tigerlils, @happyfacegirl: There is a bug with deleting objects from on certain projects that were made in the old editor. This bug has been fixed and will be out soon in a small bug fix release we are finishing up now.
In the meantime, you can easily delete those objects 3 different ways from the block editor:
1. Use the delete key in the keyboard
2. Select them and click delete from the popup menu
3. Drag them to the side of the screen.