(HELP) How to fix atrocious prediction for Japanese keyboard

I recently switched to Mac from Windows and found that when using the Japanese keyboard, the predictions are lacking compared to Windows Japanese IME and even iOS’s prediction list. While I can keep scrolling on windows and iOS to find what I need, Mac usually only gives me 1-5 predictions and is often wrong. Is there a dictionary that I can install for mac that will help me with this? Or am I missing something?