Unfortunately, there is no other way but grind

So make sure you've reached the level 5 of

• Eatery
  
• Bar
  
• Library

And only after that you need to complete the "FINAL BOSS" level

All you need to know is that time won't affect your final score (so you can take hours to solve and still get 3 stars)

On the first sight it may look challenging as hell (it is)


But I've got some tips for you:

1. Grab a piece of paper
2. Grab a pan
3. Get ready to memorize and write the stuff

I personally used top to bottom method, here how it looks



4. Write down all the symbols you see
5. If you've noticed that some of them matched, you can select them right away
6. So go top to bottom just changing the columns till you find all the paired symbols

REMEMBER: Time won't affect your star score, so take all the time you need to complete the level with 3 stars