My Ensemble startup time is about 5 minutes, all of it because it is "scanning plugins". The bizarre thing? I have 5 plugins - Synchron Player, Synchron Pianos, Vienna Instruments Pro, Kontakt 6..1.1, and Omnisphere. Closing Ensemble is not as bad, but it does still take about 2 minutes.
I am running a core i7 8700k with 64 GB of ram, Kontakt runs on a 10 TB spinning drive, everything else is installed to an M2 SSD (the libraries are all stored on a spinning drive, but the actual software and plugins are on the SSD).
This has nothing to do with the number of plugins, since I only have two plugins that are not Vienna products, and omnisphere + Kontakt are not anything unstandard. I would be surprised if anyone writing music does not have these two products installed, Ensemble should not have any issues with these two plugins.
VEP 7 is also pretty unstable, frequently crashing whenever I have a MIDI track loaded in Cubase with an instrument already loaded in Ensemble and I delete the track from within Cubase 10.4. If it didnt take 5 minutes to re-open it and another 10 minutes to load my orchestral libraries in, it wouldnt be so bad, but it sure does put a damper on creativity to have it crash and know that its going to be 15 minutes before I can start working again.
VEP 6 had no such issues, and by the time I upgraded to VEP 7, VEP 6 was so wonderfully fast and stable. I expected issues initially, but not a year after its release.