How much VRAM do you have? It actually is possible that a new save might fix some of the memory issues depending on how old the save is, but if the issue is that the image cache is too big for your GPU then there might not be a way around it
I've tried a bunch of things to optimize the game, but the main bottleneck I'm hitting right now is that Live2D requests that Ren'Py load in all of a model's images every time the model is shown. eg. Rogue has like 46 images because of all the clothing items, and they aren't that small
I've thought about trying to modify Ren'Py to check if a model's image is actually going to be used before loading, but it's not a trivial check and has some downstream consequences that I haven't felt like messing with yet
open to suggestions. right now I think something like 4 GB of VRAM is required to play the game, but even that might be pushing it