No, ram increase would only prevent crashes. The Nucleus does not swap memory to disk. If Roon runs out of RAM, it doesn’t slow down, it crashes.
Make two topics about each of those two issues with a lot more information. Both seems very off.
Search is via the internet in most cases, so if it was 5s for you, it’d be 5s for everyone, which it is not (I just searched). Something is off.