In blender 2.82.7 I can't seem to use shift+K for the knife tool

Hi, I don't know how to get the Knife Project to work in 2.8+. We now have the great multi-object edit  feature, that seems to 'destroy' the Knife Project...

In this specific case you can use my all-time favorite Blender shortcut SHIFT+CTRL+ALT+S to Shear with a value of -1:

which results in this:

or, use the knife: K (to cut), C (to constrain the cut to an angle), Z (to cut through the mesh):

Here's Gleb Alexandrov showing how to use the Knife Project in 2.8:

https://www.youtube.com/watch?v=Te0IW6YZtfc