At a minimum, you can change the interface to the old one in the game settings at any time. It appeared a long time ago, four updates ago.
On other issues, optimization is a cornerstone of RenPy, which simply cannot withstand even half of the game without cuts and other problems. Nevertheless, we are working on this in a way that no one else is working on, because the specifics of the engine are such that the larger the system, the worse the game works.