In Dolphin, in order to rename a file by pressing F2, or copy a file with Ctrl+C, you first need to select a file to be the target of that operation. This means that it's a 2-step operation: you need to click the file, and then use the desired shortcut. In single-click mode in particular, this is a more involved process, as you either need to aim for the smaller select button, or have to use Ctrl+click to select the file first.

Other file managers allow to streamline this by automatically selecting the file under the cursor (with a slight delay). That way you can just point at a file and press F2 to rename, no additional actions necessary. This is how it works in Windows Explorer when in single-click mode, in Thunar, and some other file managers, but Dolphin lacks this feature.

And alternative solution that would also achieve the same outcome would be to target file actions to the file under the cursor when no file is selected. Currently this enables the Selection Mode, but there could be a setting to instead just apply the action to the currently hovered file.

I would be happy with either solution, but there might be other factors I'm not seeing yet that make one better than the other.

This feature request comes from a thread on the KDE Discuss: https://discuss.kde.org/t/select-on-hover-in-dolphin/31489
The thread has some additional discussion about this.

Thank you.