Typing G+X or R+X is not working. Instead is asking me if I want to delete When I hit GX I'm expecting movement along the $X$ axis by an amount I type in.
Similarly, I'd expect RX$90$ to rotate the selected object(s) about the $X$-axis $90$°. Instead, the $X$ is taken as a delete command and I get a dialog box asking if OK to delete.
Is this a change in Blender or am I doing something wrong? I'd really like to be able to type SZ and a number or RX and a number.
Most likely you inadvertently deleted the shortcut in the keymaps, or you set it to something else, overriding it. Clicking on Restore in the keymaps in the preferences should clear the modification.