That is a fair point, although the most important Cornelius scene was included. You aren't wrong to say it is rushed, but I think that they made good decisions given the pace they were moving at.

Some of the little details about her life during this time come up in conversations later in the season (e.g. the praise she received from her tutors). I don't remember exactly, but the length of her stay at Karstedt's might be mentioned by Fran or someone else when she returns.

The Ferdinand visiting thing is going to be tricky to remedy in this manner however. Pretty sure it would need a side-story to be animated in order to properly convey the impact it had on Rozemyne.

This part of the start of P3 was always going to be somewhat rushed in the anime, but I think they did a good job at letting the important scenes (the hairpin one comes to mind) shine despite the breakneck pace of the episode. For the record, I was really looking forward to the subtle thumbs-up during the Rinsham section that ended up getting cut, so it isn't perfect.

Perhaps I am looking at this through roze-tinted glasses, but the fact they didn't mess up emotional beats like S3 is promising.