There should be a way to insert a -pause- in the tempo track of a specified length in SECONDS that is tied to a fermata or ’ symbol in Score. This should not require any tempo changes other than this one pause. Yes, this is not MIDI standard. Tough. It’s the way real musicians work.
Nice idea. Sibelius does this in a very raw/unpredictable way. The way it exports midi with Fermata is even stranger. It’s like it adds a a beat to the midi output which offsets the bar. I defo wouldn’t like to see that happen with cubase. But if it did it in the tempo track with an input-able pause time like you say, it could be a very elegant solution