Hello there
Well, that would depend on what quality is ur export, what are you including and of course the number of tracks. All to which contribute to taking a longer time to export.
In my case (Cubase 14, Win 10) it started a while ago but not since upgraded to C14 to take about 10 seconds to start the export, though the export itself takes a reasonable time.
It never happened in previous versions that it took time to start the export.