In general, and as unfortunate as it is. KDE has definitely been over taken in terms of performance compared to gnome. The only thing I know that runs better is something like a patchwork of LXDE components + gnome and kde libraries to make packages work without a compositor to increase performance, and sometimes I’m not even sure if you’d want to run it that way. Me myself have no problem with no transparency on your preferred shell, but preference is a big deal in terms of desktop and all the subsequent software you run to accomplish your goals.