Honestly, I’d start with free VSTs like Vital, Surge XT, or Dexed. I’ve found that they can sound way better than the stock instruments once you spend a little time tweaking the presets. Vital is especially great if you’re into synths and electronic music. I’d also look for free drum kits and sample packs, because good sounds can make a huge difference. Don’t worry about having tons of plugins either I’d pick 2–3 good ones and really learn how to use them.