In Numbers, how to navigate on text inside a cell after pressing Control+Option+U?

In Numbers we can use the ControlOptionU shortcut to edit text in a cell. Doing so the cursor goes to the end of the cell (the right side) here.

What if I want to edit in the middle of the text?

One approach might be to delete the text until the point I want to type something but I don't want to that for obvious reasons.

And if I press left/right keyboard arrows it goes to the other cell.

So how do I navigate the text in the current cell, the one I'm editing?

Perhaps I should mention I don't want to use mouse/touchpad.

You can press OptionEnter to start editing a cell the same way that double clicking will edit a cell. This will allow you to use your arrow keys, unlike ControlOptionU.

Interesting that there are two ways to do this, I wonder what the reasoning behind the command you found working the way it does is.