💖 Thanks to Person7557 for the solution.

1. Go to the game folder. You can do this in Steam by right-click on the game in your library: "Library" → "Manage" → "Browse local files" or as shown in the screenshot:
   

   

2. In the game folder right-click on Catherine.exe and select Properties.
   

   My full path for Catherine.exe: "D:\Steam\steamapps\common\CatherineClassic\Catherine.exe"

3. In the Properties window, go to the Compatibility tab and enable compatibility with Windows 95:
   

   

4. Enjoy. 🙂

1. Download the Windows ADK [learn.microsoft.com];
   
2. During installation, it gives the option to select multiple tools. The only one needed is «Compatibility Administrator». You can see then on top in «Application Compatibility Tools»;
   
3. Once installed, open the Start Menu folder named Windows Kits and launch Compatiblity Administrator (32-bit);
   

   My Full Path:
   "C:\Program Files (x86)\Windows Kits\10\Assessment and Deployment Kit\Application Compatibility Toolkit\Compatibility Administrator (32-bit)\Compatadmin.exe"

4. Select the new database under custom databases;

   

5. Right Click on New Database. In the database menu -> Create New -> Application Fix;
   

   

6. Provide the full path of Catherine.exe and give it a name of choosing;
   

   

7. Skip past the compatibility mode options;
   
8. In compatibility fixes select ProcessorCountLieForHybridCPU;
   

   

9. Save the database from the Database menu and give it a name when prompted;
   

   
   I saved my db in the game folder: "D:\Steam\steamapps\common\CatherineClassic\dbcc.sdb"

10. Select File -> Install. Now the fix will automatically be applied whenever the game is launched.
    

    

11. Enjoy. 🙂