So let's see if I understood it. The main differences between Quick Resume and Activity cards/Switcher are:
Quick Resume
-Resumes exactly where you left the game in the last game session. So you can 'resume' to a single point of the game.
-Not all games support it (at least some of them due to a bug that will be fixed)
-Works with a few games you recently played (up to 5 Series X games or 12 BC games), not all the ones you have installed in the console
-Requires dozens of SSD GBs because basically dumps the game RAM in the SSD
Activity cards/Switcher
-In all PS5 games is a cold boot + resumes to your last checkpoint savedata in the last game session or acts as quick, direct access to specific tasks, stages or game modes skipping menus/logos (varies per game). So you can 'resume' to multiple points in each game.
-All PS5 games support it (in PS4 games it's only a quick access to cold boot the game)
-Works in all the games you have installed in the console, not with the few you recently played
-Doesn't require extra SSD space because it basically uses the normal savedata
Please can someone correct me if I'm wrong in something?