Is it possible to have a large notification appear and stay on screen?

May I ask what is the purpose of displaying your cheatsheet?
If it is to select a Macro to trigger, then I'd suggest using MACRO: Execute Macro by Name (Spotlight) by @DanThomas.

It is very fast, and the type-select is very smart -- you can use separate words in the search box to add to the filter.
While it does not display the hotkey in the list, when you select (but not yet choose by RETURN), it displays the hot keys at the bottom of the window).

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I use it many times a day, and love it.