Keyboard shortcuts: how to bulk re-define meta to R_ctrl?

With the upgrade to KDE/Plasma 6 the keyboard shortcuts seem to have changed. In particular, Ctrl-Esc used to bring up the system monitor. That now seems to have been remapped to Meta-Esc.

I know this might be very retro, but I prefer to use my ca. 30 year old IBM 102-key keyboard (yes, I’m hip for the click). This does not have a Meta key. Is there any way to bulk re-map all Meta-key shortcuts to something else, say the right Ctlr-key?
Alternatively, is there any way to bring back the KDE5 setup?

PS: On a side note: with the 102-key generic keyboard set up in KDE, it would be nice to have the default keybindings automatically set up appropriately.