• Proton is a free software embedded in Steam that allows you to -try- to make your games running on Linux even if your games aren't natively running on Linux. Can be refered as Steam Play.
  
• Wine is a free software that you can download on your Linux to make Windows softwares -maybe- run on your Linux.

To see if your chances are the best on Linux for games that aren't made for Linux, check everytime the website ProtonDB : https://www.protondb.com
And/or WineHQ : https://www.winehq.org/

If Proton isn't available for all your games do that :
"On top-left corner click on Steam -> Settings -> Steam Play and tick "Enable Steam Play for all titles"
https://gtm.steamproxy.vip/app/221410/discussions/0/1734336452577465748/?l=spanish

If you haven't, follow the first section of this guide to enable Proton on all your games if it isn't available for that one. Then, we will try to use Proton on Restaurant Empire 2.

• Go to your library.
  
• Right click on your game.
  
• Settings.
  
• Compatibility.
  
• Check force the use of a spectific Steam Play compatibility tool.
  
• I personally use Proton 4.2 because it runs smoother for me but it's up to you to choose.
  
• Now go to General.
  
• As mentionned in the ProtonDB post : Use following launch-option to fix the cutscene crash: PROTON_USE_D9VK=1 %command%
  
• Close the settings, launch the game, be patient.
  
• If that doesn't work, leave a comment here and/or go to the Wine section of this guide.

Install Wine via your Ubuntu Software app on Ubuntu.
Now, if you still have issues with Proton and you have Wine installed on your computer :

• Library.
  
• Right click on the game.
  
• Browse local files.
  
• If you are on Ubuntu right click on the directory, open with terminal.
  
• type "Wine re2.exe"

The game should work without music but with sounds.
If you doesn't understand a part, have any issue understanding a word/part of this guide, leave a comment.

Thank you for reading.