Dolphin Question

I want to reassign the open folder in dolphin with return → spacebar (or alt+space or something else, I understand if there should be some restrictions for some reason), but I cannot find the configuration line anywhere in the Dolphin settings, and I have not found it online.
I understand that I don’t need it for keyboard-only operation, but I have to use the keyboard with one hand, and because of other common keyboard shortcuts (alt+f4, ctrl+w, etc.) I have to keep my hand on the left side, and that is too far from the return key.
There is already an “Up” hotkey for folders, so why not make “Open” (aka “Down” in the tree)?