Bug 451901

SUMMARY
I was a huge fan of the old Cover Switch and Flip Switch effects and was disappointed to see they had been removed.  Today I decided to look again and, lo and behold, there they were!

I have a couple problems with the new ones, though, that until they're improved will sadly keep me from using them:

1. First, and most importantly, performance is nowhere near as good - or at least nowhere near as smooth.  I have a fairly decent machine - Ryzen 5 5500U, 32GB of memory, integrated graphics - and the new effects don't feel like they're hitting my external monitor's 75FPS.  On the laptop's internal display they aren't smooth either.  The old effects were quite smooth even on my Pinebook Pro (which is a much slower machine).
2. Second, and less importantly, the new implementations simply don't look as nice as the old ones.  The slightly-transparent solid gray background is drab and boring, reflections are missing, the animations aren't as polished, thumbnails are too small, there are no start/end animations, and quick-switching tasks doesn't look right.


SOFTWARE/OS VERSIONS
KDE Plasma Version: 5.24.3
KDE Frameworks Version: 5.92.0
Qt Version: 5.15.3

ADDITIONAL INFORMATION
This is similar to #449180 and #450230.