Mine takes a few seconds to open on my Mac, its nowhere near as ‘instant’ as Logic Pro is, I think even Ableton Live 11 opens a little quicker, if I dont have any new plugins to scan.
Cubase probably takes about 10-20 seconds to open here, but I’m on an i7 Mac Mini (Ventura 13.2.1) so its not the latest/greatest all powerful M1/M2 machine or anything. Prior to the .52 update, I removed the vstconnect plugin, along with the video plugin and made the startup REALLY quick, but after updating, it reinstalled them and I never bothered removing them again…