With the latest Nuendo 14.030 update, it seems the issue with sluggish behavior when dragging or trimming audio events in very large sessions (such as TV series projects with multiple episodes on the timeline for reference) has been resolved, great improvement there.
However, trimming or adjusting cycle markers still remains very sluggish. I’m also noticing that video playback is occasionally choppy. I always use Avid DNxHD codecs, so this is consistent across large sessions.
Just to reiterate: when opening the exact same sessions in Nuendo 13.055, none of these issues occur.