It's not possible to open folder with one click in default "Icons" view in Finder. However switching to "Columns" view (<Cmd>+3
cmd-3) will allow you to open folder with one click.
Also it could be faster to just use hotkeys instead of trackpad/mouse. Use arrows to navigate inside "Icons" view, <Cmd>+<Arrow Down>
cmd-down to open selected folder and <Enter>
enter to rename selected file or folder. When no file or folder is selected, you could just type in file/folder name and Finder will select closest match for you.