Part of the issue is going to be how it figures out what to run on what. Is this going to need application changes, which you may not have access to (support plans or companies dead etc)? or at least an application manifests. Not to mention cheating...
It does make sense in some ways to dump things that do not need high power cores to low power ones, like email or Skype/Teams apps etc. Would save on power. But at the same time your dedicating die space to something most people dont really need and will likely give up primary CPU power for in some way ( cache, GPU etc).
If you can't pin your app, I can imagine the chaos, your playing a game and it spins up another background thread and it gets put on a weak core and your game goes from running fine to a slideshow.