When working with multiple applications, I wish to group the visibility of 2 or more app/windows together, so they either minimize all or visible all, not necessarily maximized. Eg, say I want to have VsCode and Firefox visibility grouped so when I minimize VsCode, Firefox is also minimized and I can browse the web with Chrome full screen. Later when I restore VsCode then Firefox is also restored automatically.
I am aware of an extension called ShellTile that has grouping capability, but it appears to tile 2 applications fullscreen side by side which is not what I want.
That is what dynamic workspaces in Gnome Shell are primarily designed for. They are not as much intended/setup to separate different activities. Rather, they are intended to create different visual contexts for your applications.
Put your VsCode and Firefox visibility grouped on one workspace. Open Chromium on the next workspace. Using Alt+Tab or switching applications using the Dock or Dash, you seamlessly switch between the two groups as if they were on the same workspace. Yet, they are visually separated.
Just try that workflow. You will see it works neatly for what you are after.