Better libraries do tend to be bigger, on the whole. Also, if you did decide to get a decent sample library, would you want to tinker with it yourself, adjusting the dynamics, note timings and so on? You could let NotePerformer do that stuff for you (if you chose a library that it works with) but that would probably require more RAM. For example, 32 GB is the recommended minimum for the EastWest Hollywood Opus Orchestra, but 64 GB is recommended if you want to use it with NotePerformer.
Come to think of it, do you even have NotePerformer? If not, get the demo and compare it with the sound you get from HALion. It doesn’t need much RAM, if you don’t want to use it in conjunction with a sample library.