Add some kind of "Add Inside" functionality for containers, similar to Add Before and Add After

[MadtownLems]

What problem does this address?

List view, and the 3 dot menu in the block toolbar, and the Command Palette all offer convenient links "Add before" and "Add after" for blocks. There's currently not a convenient way to Add a block INSIDE of the currently selected block in the same way. For example, in this screenshot, I'd like to be able to easily insert a block inside of the group that I've named "Upper Content".

What is your proposed solution?

For blocks such as Group Blocks (Row, Stack, Grid, etc - or perhaps even all blocks that support InnerBlocks), offer a similar shortcut for "Add inside".